Re: Dependency / Constraint patch - Mailing list pgsql-patches

All that, and I forgot the actual patch.

Attached.

--
Rod
----- Original Message -----
From: "Rod Taylor" <rbt@zort.ca>
To: <pgsql-patches@postgresql.org>
Sent: Saturday, June 15, 2002 3:10 PM
Subject: [PATCHES] Dependency / Constraint patch


> Differences from previous version:
> - Fully functional ALTER TABLE / DROP CONSTRAINT
> - pg_dump uses ALTER TABLE / ADD FOREIGN KEY
> - psql displays foreign keys (\d output)
> - Foreign key triggers are autonamed based on the constraint name
> - Namespace dependencies were quickly added.  Unable to test them
very
> well (DROP SCHEMA required)
>
>
> Postgresql TODO items completed (or very close):
> # Add ALTER TABLE DROP non-CHECK CONSTRAINT
> # Allow psql \d to show foreign keys
> *  Add pg_depend table for dependency recording; use sysrelid, oid,
> depend_sysrelid, depend_oid, name
> # Auto-destroy sequence on DROP of table with SERIAL
> # Prevent column dropping if column is used by foreign key
> # Automatically drop constraints/functions when object is dropped
> # Make constraints clearer in dump file
> # Make foreign keys easier to identify
>
>
>
> The locking of relations may not be as strong as it should be.  I
was
> unable to cause failure -- and can't see what it would be missing
but it
> has been bothering me.
>
> I've not touched pg_dump for SERIAL stuff.  I may do it later.
>
> Basic documentation updates included.  I'll scour for examples or
notes
> which may no longer apply in a couple of weeks.
>
>
> Attached files:
>
> TODO.depend - A short list of items I completed, notes, any
assumptions,
> and possible outstanding items
>
> src/backend/catalog/pg_constraint.c
> src/backend/catalog/pg_depend.c
> src/include/catalog/pg_constraint.h
> src/include/catalog/pg_depend.h
> src/test/regress/expected/drop.out
>
> Remove:
> src/backend/catalog/pg_relcheck.c
> src/include/catalog/pg_relcheck.h
>
>
>


----------------------------------------------------------------------
----------


>
> CHANGES
> -------
> initdb process has been changed in an attempt to automatically pin
some basic types.
> pg_type and pg_proc currently.
>
> pg_relcheck replaced with more generic pg_constraint.
>
> Nearly all objects have an enforced RESTRICT / CASCADE except for in
'compiled' expressions.
> Ie.  Views, function contents, default expressions,
>
>
>
> [-] completed
> [*] yet to do
> - Create Type
> - Create View
> * Create View (on precompile set deps in source)
> - Create Trigger
> - Create Table (Columns on Types)
> * Create Table / Column Defaults (on precompile set deps in source)
> - Create Sequence (currval, nextval, setval are PINNED)
> - Create Rule (always cascade)
> - Create Operator
> - Create Language
> - Create Index
> - Create Function
> * Create Function (on precompile set additional deps in source)
> - Create Aggregate
>
> - Drop Type (regress tested)
> - Drop View
> - Drop Trigger
> - Drop Table
> - Drop Sequence
> - Drop Rule
> - Drop Operator
> - Drop Language
> - Drop Index
> - Drop Function (regress tested)
> - Drop Aggregate
>
> - Alter Table / Primary Key
> - Alter Table / unique index
> * Alter Table / Default (Compiled default depends on functions /
types within)
> - Alter Table / Add Column
> - Alter table / add column which creates toast table
> - Alter Table / Drop Constraint (Fixed to function as expected)
>
>
> - Drop pg_relcheck
> - Create pg_constraint
>
> - Insert check constraints into pg_constraint
>
> - Insert unique constraints into pg_constraint
> - Have unique key indicies depend on pg_constraint (implicit
cascade)
> - Insert primary key constraints into pg_constraint
> - Have primary key indicies depend on pg_constraint (implicit
cascade)
> - Insert foreign key constraints into pg_constraint
> - Have foreign key triggers depend on pg_constraint
> - Have pg_constraint depend on the table columns (not the table
itself)
> - heap.c - Drop RemoveRelChecks()
> - pg_constraint - ConstraintCreate dependencies
>
> - Base type dependency on array type managed by pg_depend (always
cascaded)
> - Table drop foreign key triggers as managed by pg_depend (always
cascaded)
> - Toast tables depend on relation (always cascade)
> - Enable opt_behaviour for most items in gram.y
> - Disallow base functionality (types, procedures, and catalogs
required for operation) to be dropped ever
> - Implicit drop of a SERIALs sequence (regress tested)
>
> - Alter Table / Drop Constraint
(tablecmds->AlterTableDropConstraint)
>
> - Enable psql to view check and foreign key constraints (\d) on
table definition
> - Have pg_dump use ALTER TABLE commands for Foreign Keys
> - Move Foreign Key constraint trigger creation to constraintCreate()
from analyze.c.
> - Name triggers after the constraints -- but append a number and
guarentee uniqueness
>
>
> OTHER NOTES
> -----------
>
> CREATE TABLE tab (col1 int4 DEFAULT nextval('seq'));
> - DROP FUNCTION nextval(text) CASCADE;
> - Drop the column (col1) or set the default to NULL?
>
> Do objects depend on users (ownership)?  ie. DROP USER CASCADE to
dump everything they own when they're removed?
>
> Unique constraints for indicies have unique names across BOTH
pg_constraint and pg_index.  pg_constraint
> is unique to relid and index name so it's not that bad.
>
> One can drop a unique index without the constraint being dropped
(DOH!).  Attempts to fix cause circular dependency.
>
>
> ALTER TABLE DROP COLUMN should allow foreign key relations to only
drop the foreign column, not the whole relation.
>
> CASCADEd drops should occur regardless of ownership of objects other
than the one specifically specified (parent of cascade)
>
> Change foreign keys to work through a set of constraint functions
using definitions from pg_constraint rather than doing work in the
parser.
>


----------------------------------------------------------------------
----------


>
/*--------------------------------------------------------------------
-----
>  *
>  * pg_constraint.c
>  *   routines to support manipulation of the pg_namespace relation
>  *
>  * Portions Copyright (c) 1996-2001, PostgreSQL Global Development
Group
>  * Portions Copyright (c) 1994, Regents of the University of
California
>  *
>  *
>  * IDENTIFICATION
>  *   $Header$
>  *
>
*---------------------------------------------------------------------
----
>  */
> #include "postgres.h"
>
> #include "access/heapam.h"
> #include "access/genam.h"
> #include "catalog/catname.h"
> #include "catalog/indexing.h"
> #include "catalog/pg_constraint.h"
> #include "catalog/pg_namespace.h"
> #include "catalog/pg_depend.h"
> #include "commands/trigger.h"
> #include "nodes/makefuncs.h"
> #include "nodes/parsenodes.h"
> #include "parser/gramparse.h"
> #include "utils/array.h"
> #include "utils/builtins.h"
> #include "utils/fmgroids.h"
> #include "utils/lsyscache.h"
> #include "utils/syscache.h"
>
> /*
>  * ConstraintCreate
>  * Create the constraint table portion as well as any dependencies.
>  */
> Oid
> constraintCreate(Oid relId,
> const char *constraintName,
> char constraintType,
> bool isDeferrable,
> bool isDeferred,
> const AttrNumber *constraintKey,
> int constraintNKeys,
> Oid foreignRelId,
> const AttrNumber *foreignKey,
> int foreignNKeys,
> char foreignUpdateType,
> char foreignDeleteType,
> char foreignMatchType,
> char *conBin,
> char *conSrc)
> {
> Relation conDesc;
> HeapTuple tup;
> char nulls[Natts_pg_constraint];
> Datum values[Natts_pg_constraint];
> int i = 0;
> Oid conOid;
> Datum conkey[constraintNKeys];
> Datum confkey[foreignNKeys];
> SysScanDesc rcscan;
> ScanKeyData skey[2];
> ObjectAddress myself,
> dependee;
> NameData cname;
>
> conDesc = heap_openr(ConstraintRelationName, RowExclusiveLock);
>
> /* sanity checks */
> if (!constraintName)
> {
> namestrcpy(&cname, getConstraintName(relId));
> }
> else
> {
> namestrcpy(&cname, constraintName);
>
> /* make sure there is no existing constraints of the same name */
> ScanKeyEntryInitialize(&skey[i++],
>    0, Anum_pg_constraint_conrelid, F_OIDEQ,
>    ObjectIdGetDatum(relId));
>
> ScanKeyEntryInitialize(&skey[i++],
>    0, Anum_pg_constraint_conname, F_NAMEEQ,
>    NameGetDatum(&cname));
>
> rcscan = systable_beginscan(conDesc, ConstraintRelidNameIndex, true,
> SnapshotNow,
> i, skey);
>
> tup = systable_getnext(rcscan);
> if (HeapTupleIsValid(tup))
> elog(ERROR, "constraint \"%s\" already exists", NameStr(cname));
>
> systable_endscan(rcscan);
> }
>
>
> /* Build Datum array for ConstraintKey */
> for (i = 0; i < constraintNKeys; i++)
> conkey[i] = Int16GetDatum(constraintKey[i]);
>
> /*
> * Build Datum array for foreignKey. Use a
> * placeholder entry if otherwise NULL.
> */
> if (foreignNKeys && foreignNKeys > 0)
> for (i = 0; i < foreignNKeys; i++)
> confkey[i] = Int16GetDatum(foreignKey[i]);
> else
> confkey[0] = Int16GetDatum(0);
>
>
> /* initialize nulls and values */
> for (i = 0; i < Natts_pg_constraint; i++)
> {
> nulls[i] = ' ';
> values[i] = (Datum) NULL;
> }
>
> values[Anum_pg_constraint_conrelid - 1] = ObjectIdGetDatum(relId);
> values[Anum_pg_constraint_conname - 1] = NameGetDatum(&cname);
> values[Anum_pg_constraint_contype - 1] =
CharGetDatum(constraintType);
> values[Anum_pg_constraint_condeferrable - 1] =
BoolGetDatum(isDeferrable);
> values[Anum_pg_constraint_condeferred - 1] =
BoolGetDatum(isDeferred);
> values[Anum_pg_constraint_conkey - 1] =
PointerGetDatum(construct_array(conkey,
> constraintNKeys,
> true, 2, 'i'));
>
> /* Record what we were given, or a placeholder if NULL */
> if (foreignRelId)
> values[Anum_pg_constraint_confrelid - 1] =
ObjectIdGetDatum(foreignRelId);
> else
> values[Anum_pg_constraint_confrelid - 1] =
ObjectIdGetDatum(InvalidOid);
>
> /* Record what we were given, or a placeholder if NULL */
> values[Anum_pg_constraint_confkey - 1] =
PointerGetDatum(construct_array(confkey,
> foreignNKeys > 0 ? foreignNKeys : 1,
> true, 2, 'i'));
>
> /* Record what we were given, or a placeholder if NULL */
> if (foreignUpdateType)
> values[Anum_pg_constraint_confupdtype - 1] =
CharGetDatum(foreignUpdateType);
> else
> values[Anum_pg_constraint_confupdtype - 1] =
CharGetDatum(CONSTRAINT_FKEY_RESTRICT);
>
> /* Record what we were given, or a placeholder if NULL */
> if (foreignDeleteType)
> values[Anum_pg_constraint_confdeltype - 1] =
CharGetDatum(foreignDeleteType);
> else
> values[Anum_pg_constraint_confdeltype - 1] =
CharGetDatum(CONSTRAINT_FKEY_RESTRICT);
>
> /* Record what we were given, or a placeholder if NULL */
> if (foreignMatchType)
> values[Anum_pg_constraint_confmatchtype - 1] =
CharGetDatum(foreignMatchType);
> else
> values[Anum_pg_constraint_confmatchtype - 1] =
CharGetDatum(CONSTRAINT_FKEY_FULL);
>
> /*
> * initialize the binary form of the check constraint.
> */
> if (conBin)
> values[Anum_pg_constraint_conbin - 1] = DirectFunctionCall1(textin,
> CStringGetDatum(conBin));
> else
> nulls[Anum_pg_constraint_conbin - 1] = 'n';
>
> /*
> * initialize the text form of the check constraint
> */
> if(conSrc)
> values[Anum_pg_constraint_consrc - 1] = DirectFunctionCall1(textin,
> CStringGetDatum(conSrc));
> else
> nulls[Anum_pg_constraint_consrc - 1] = 'n';
>
> tup = heap_formtuple(RelationGetDescr(conDesc), values, nulls);
> if (!HeapTupleIsValid(tup))
> elog(ERROR, "ConstraintCreate: heap_formtuple failed");
>
> conOid = simple_heap_insert(conDesc, tup);
> if (!OidIsValid(conOid))
> elog(ERROR, "ConstraintCreate: heap_insert failed");
>
> /* Handle Indicies */
> if (RelationGetForm(conDesc)->relhasindex)
> {
> Relation idescs[Num_pg_constraint_indices];
>
> CatalogOpenIndices(Num_pg_constraint_indices,
Name_pg_constraint_indices, idescs);
> CatalogIndexInsert(idescs, Num_pg_constraint_indices, conDesc, tup);
> CatalogCloseIndices(Num_pg_constraint_indices, idescs);
> }
>
> /*
> * Handle Dependencies
> */
> myself.classId = RelationGetRelid(conDesc);
> myself.objectId = conOid;
> myself.objectSubId = 0;
>
> /* The constraint depends on the relation */
> dependee.classId = RelOid_pg_class;
> dependee.objectId = relId;
> dependee.objectSubId = 0;
> dependCreate(&myself, &dependee, true);
>
>
> /*
> * The constraint depends on the foreign relation columns
> *
> * Relation dependencies are skipped if we depend
> * directly on ourselves
> */
> if (foreignNKeys && foreignNKeys > 0
> && relId != foreignRelId)
> {
> Assert(foreignNKeys = constraintNKeys);
>
> for (i = 0; i < foreignNKeys; i++)
> {
> ObjectAddress depender;
> depender.classId = RelOid_pg_class;
> depender.objectId = relId;
> depender.objectSubId = conkey[i];
>
> dependee.classId = RelOid_pg_class;
> dependee.objectId = foreignRelId;
> dependee.objectSubId = foreignKey[i];
> dependCreate(&depender, &dependee, false);
>
> dependCreate(&myself, &dependee, true);
> }
> }
>
> /*
> * Create the required triggers to enforce the requested
> * foreign key constraint.  Record dependencies of the
> * trigger to the FK Constraint.
> */
> if (foreignNKeys && foreignNKeys > 0)
> {
> CreateTrigStmt *fk_trigger;
> Oid trigId;
> RangeVar    *foreignRel;
> RangeVar    *localRel;
> char    *foreignNameSpace;
> char    *localNameSpace;
> char    *foreignRelation;
> char    *localRelation;
> char    *mType = "UNSPECIFIED";
>
> /* Pull relation names */
> foreignNameSpace =
get_namespace_name(get_rel_namespace(foreignRelId));
> localNameSpace = get_namespace_name(get_rel_namespace(relId));
>
> foreignRelation = get_rel_name(foreignRelId);
> localRelation = get_rel_name(relId);
>
> localRel = makeRangeVar(localNameSpace, localRelation);
> foreignRel = makeRangeVar(foreignNameSpace, foreignRelation);
>
> /* Find the trigger name for match types */
> switch (foreignMatchType)
> {
> case CONSTRAINT_FKEY_FULL:
> mType = "FULL";
> break;
> case CONSTRAINT_FKEY_PARTIAL:
> mType = "PARTIAL";
> break;
> case CONSTRAINT_FKEY_UNSPECIFIED:
> mType = "UNSPECIFIED";
> break;
> default:
> elog(ERROR, "constraintCreate: Unknown MATCH TYPE");
> }
>
> /* Double check keys align */
> Assert(foreignNKeys = constraintNKeys);
>
> /*
> * Build a CREATE CONSTRAINT TRIGGER statement for the CHECK
> * action.
> */
> fk_trigger = (CreateTrigStmt *) makeNode(CreateTrigStmt);
> fk_trigger->trigname = getTriggerName(relId, NameStr(cname));
> fk_trigger->relation = localRel;
> fk_trigger->funcname = SystemFuncName("RI_FKey_check_ins");
> fk_trigger->before = false;
> fk_trigger->row = true;
> fk_trigger->actions[0] = 'i';
> fk_trigger->actions[1] = 'u';
> fk_trigger->actions[2] = '\0';
> fk_trigger->lang = NULL;
> fk_trigger->text = NULL;
>
> fk_trigger->attr = NIL;
> fk_trigger->when = NULL;
> fk_trigger->isconstraint = true;
> fk_trigger->deferrable = isDeferrable;
> fk_trigger->initdeferred = isDeferred;
> fk_trigger->constrrel = foreignRel;
>
> fk_trigger->args = NIL;
> fk_trigger->args = lappend(fk_trigger->args,
>    makeString(NameStr(cname)));
> fk_trigger->args = lappend(fk_trigger->args,
>    makeString(localRel->relname));
> fk_trigger->args = lappend(fk_trigger->args,
> makeString(foreignRel->relname));
> fk_trigger->args = lappend(fk_trigger->args,
>    makeString(mType));
> for (i = 0; i < foreignNKeys; i++)
> {
> fk_trigger->args = lappend(fk_trigger->args,
>    makeString(get_attname(relId, constraintKey[i])));
> fk_trigger->args = lappend(fk_trigger->args,
>    makeString(get_attname(foreignRelId, foreignKey[i])));
> }
>
> trigId = CreateTrigger(fk_trigger);
>
> /* The trigger depends on the constraint */
> dependee.classId = get_relname_relid(TriggerRelationName,
PG_CATALOG_NAMESPACE);;
> dependee.objectId = trigId;
> dependee.objectSubId = 0;
> dependCreate(&dependee, &myself, true);
>
> /*
> * Bump the command counter to prevent the next trigger
> * from attempting to use the same name as the previous
> */
> CommandCounterIncrement();
>
> /*
> * Build a CREATE CONSTRAINT TRIGGER statement for the ON DELETE
> * action fired on the PK table !!!
> */
> fk_trigger = (CreateTrigStmt *) makeNode(CreateTrigStmt);
> fk_trigger->trigname = getTriggerName(foreignRelId, NameStr(cname));
> fk_trigger->relation = foreignRel;
> fk_trigger->before = false;
> fk_trigger->row = true;
> fk_trigger->actions[0] = 'd';
> fk_trigger->actions[1] = '\0';
> fk_trigger->lang = NULL;
> fk_trigger->text = NULL;
>
> fk_trigger->attr = NIL;
> fk_trigger->when = NULL;
> fk_trigger->isconstraint = true;
> fk_trigger->deferrable = isDeferrable;
> fk_trigger->initdeferred = isDeferred;
> fk_trigger->constrrel = localRel;
> switch (foreignDeleteType)
> {
> case CONSTRAINT_FKEY_NOACTION:
> fk_trigger->funcname = SystemFuncName("RI_FKey_noaction_del");
> break;
> case CONSTRAINT_FKEY_RESTRICT:
> fk_trigger->deferrable = false;
> fk_trigger->initdeferred = false;
> fk_trigger->funcname = SystemFuncName("RI_FKey_restrict_del");
> break;
> case CONSTRAINT_FKEY_CASCADE:
> fk_trigger->funcname = SystemFuncName("RI_FKey_cascade_del");
> break;
> case CONSTRAINT_FKEY_NULL:
> fk_trigger->funcname = SystemFuncName("RI_FKey_setnull_del");
> break;
> case CONSTRAINT_FKEY_DEFAULT:
> fk_trigger->funcname = SystemFuncName("RI_FKey_setdefault_del");
> break;
> }
>
> fk_trigger->args = NIL;
> fk_trigger->args = lappend(fk_trigger->args,
>    makeString(NameStr(cname)));
> fk_trigger->args = lappend(fk_trigger->args,
>    makeString(localRel->relname));
> fk_trigger->args = lappend(fk_trigger->args,
> makeString(foreignRel->relname));
> fk_trigger->args = lappend(fk_trigger->args,
>    makeString(mType));
> for (i = 0; i < foreignNKeys; i++)
> {
> fk_trigger->args = lappend(fk_trigger->args,
>    makeString(get_attname(relId, constraintKey[i])));
> fk_trigger->args = lappend(fk_trigger->args,
>    makeString(get_attname(foreignRelId, foreignKey[i])));
> }
>
> trigId = CreateTrigger(fk_trigger);
>
> /* The trigger depends on the constraint */
> dependee.classId = get_relname_relid(TriggerRelationName,
PG_CATALOG_NAMESPACE);;
> dependee.objectId = trigId;
> dependee.objectSubId = 0;
> dependCreate(&dependee, &myself, true);
>
> /*
> * Bump the command counter to prevent the next trigger
> * from attempting to use the same name as the previous
> */
> CommandCounterIncrement();
>
>
> /*
> * Build a CREATE CONSTRAINT TRIGGER statement for the ON UPDATE
> * action fired on the PK table !!!
> */
> fk_trigger = (CreateTrigStmt *) makeNode(CreateTrigStmt);
> fk_trigger->trigname = getTriggerName(foreignRelId, NameStr(cname));
> fk_trigger->relation = foreignRel;
> fk_trigger->before = false;
> fk_trigger->row = true;
> fk_trigger->actions[0] = 'u';
> fk_trigger->actions[1] = '\0';
> fk_trigger->lang = NULL;
> fk_trigger->text = NULL;
>
> fk_trigger->attr = NIL;
> fk_trigger->when = NULL;
> fk_trigger->isconstraint = true;
> fk_trigger->deferrable = isDeferrable;
> fk_trigger->initdeferred = isDeferred;
> fk_trigger->constrrel = localRel;
> switch (foreignUpdateType)
> {
> case CONSTRAINT_FKEY_NOACTION:
> fk_trigger->funcname = SystemFuncName("RI_FKey_noaction_upd");
> break;
> case CONSTRAINT_FKEY_RESTRICT:
> fk_trigger->deferrable = false;
> fk_trigger->initdeferred = false;
> fk_trigger->funcname = SystemFuncName("RI_FKey_restrict_upd");
> break;
> case CONSTRAINT_FKEY_CASCADE:
> fk_trigger->funcname = SystemFuncName("RI_FKey_cascade_upd");
> break;
> case CONSTRAINT_FKEY_NULL:
> fk_trigger->funcname = SystemFuncName("RI_FKey_setnull_upd");
> break;
> case CONSTRAINT_FKEY_DEFAULT:
> fk_trigger->funcname = SystemFuncName("RI_FKey_setdefault_upd");
> break;
> }
>
> fk_trigger->args = NIL;
> fk_trigger->args = lappend(fk_trigger->args,
>    makeString(NameStr(cname)));
> fk_trigger->args = lappend(fk_trigger->args,
>    makeString(localRel->relname));
> fk_trigger->args = lappend(fk_trigger->args,
> makeString(foreignRel->relname));
> fk_trigger->args = lappend(fk_trigger->args,
>    makeString(mType));
> for (i = 0; i < foreignNKeys; i++)
> {
> fk_trigger->args = lappend(fk_trigger->args,
>    makeString(get_attname(relId, constraintKey[i])));
> fk_trigger->args = lappend(fk_trigger->args,
>    makeString(get_attname(foreignRelId, foreignKey[i])));
> }
>
> trigId = CreateTrigger(fk_trigger);
>
> /* The trigger depends on the constraint */
> dependee.classId = get_relname_relid(TriggerRelationName,
PG_CATALOG_NAMESPACE);;
> dependee.objectId = trigId;
> dependee.objectSubId = 0;
> dependCreate(&dependee, &myself, true);
> }
>
> /* Cleanup, but keep lock */
> heap_close(conDesc, NoLock);
>
> return conOid;
> }
>
>
> char *
> getConstraintName(Oid relId)
> {
> int j = 1;
> bool success;
> Relation conDesc;
> HeapTuple tup;
> char    *cname;
>
> cname = palloc(NAMEDATALEN * sizeof(char));
>
> conDesc = heap_openr(ConstraintRelationName, RowExclusiveLock);
>
> /* Loop until we find a non-conflicting constraint name */
> /* What happens if this loops forever? */
> do
> {
> int i = 0;
> SysScanDesc rcscan;
> ScanKeyData skey[2];
>
> success = false;
>
> snprintf(cname, NAMEDATALEN, "constraint_%d", j);
>
> /* make sure there is no existing constraints of the same name */
> ScanKeyEntryInitialize(&skey[i++],
>    0, Anum_pg_constraint_conrelid, F_OIDEQ,
>    ObjectIdGetDatum(relId));
>
> ScanKeyEntryInitialize(&skey[i++],
>    0, Anum_pg_constraint_conname, F_NAMEEQ,
>    NameGetDatum(cname));
>
> rcscan = systable_beginscan(conDesc, ConstraintRelidNameIndex, true,
> SnapshotNow,
> i, skey);
>
> tup = systable_getnext(rcscan);
> if (!HeapTupleIsValid(tup))
> success = true;
>
> systable_endscan(rcscan);
> ++j;
> } while (!success);
>
> /* Cleanup, but keep lock */
> heap_close(conDesc, NoLock);
>
> return cname;
> }
>
> void
> DropConstraintById(Oid conId, int behavior)
> {
> ObjectAddress myself;
> Relation conDesc;
> HeapTuple tup;
> ScanKeyData skey[1];
> SysScanDesc rcscan;
> int i = 0;
> Relation ridescs[Num_pg_class_indices];
> Form_pg_constraint con;
>
> /* Better be a valid Id */
> Assert(OidIsValid(conId));
>
> /* CONSTRAINT */
> ScanKeyEntryInitialize(&skey[i++],
>    0, ObjectIdAttributeNumber, F_OIDEQ,
>    ObjectIdGetDatum(conId));
>
> conDesc = heap_openr(ConstraintRelationName, RowExclusiveLock);
> rcscan = systable_beginscan(conDesc, ConstraintOidIndex, true,
> SnapshotNow,
> i, skey);
>
> tup = systable_getnext(rcscan);
>
>
> /*
> * Due to circular constraint dependencies we simply
> * skip the drop when we don't find the constraint rather
> * than the below:
> *
> *
> */
> if (!HeapTupleIsValid(tup))
> elog(ERROR, "Constraint OID %d missing", conId);
>
> con = (Form_pg_constraint) GETSTRUCT(tup);
>
> /*
> * Now we need to update the relcheck count
> * if it was a check constraint being dropped
> */
> if (con->contype == CONSTRAINT_CHECK)
> {
> Relation rel;
> HeapTuple relTup;
>
> rel = heap_openr(RelationRelationName, RowExclusiveLock);
>
> relTup = SearchSysCache(RELOID,
> ObjectIdGetDatum(con->conrelid),
> 0, 0, 0);
> if (!HeapTupleIsValid(relTup))
> elog(ERROR, "DropConstraintById: Relation Tuple non-existant");
>
> ((Form_pg_class) GETSTRUCT(relTup))->relchecks -= 1;
>
> simple_heap_update(rel, &relTup->t_self, relTup);
> CatalogOpenIndices(Num_pg_class_indices, Name_pg_class_indices,
ridescs);
> CatalogIndexInsert(ridescs, Num_pg_class_indices, rel, relTup);
> CatalogCloseIndices(Num_pg_class_indices, ridescs);
>
> ReleaseSysCache(relTup);
>
> heap_close(rel, RowExclusiveLock);
> }
>
> /* Fry the constraint itself*/
> simple_heap_delete(conDesc, &tup->t_self);
>
> /* Clean up */
> systable_endscan(rcscan);
> heap_close(conDesc, RowExclusiveLock);
>
> /* Deal with dependencies */
> myself.classId = get_relname_relid(ConstraintRelationName,
PG_CATALOG_NAMESPACE);
> myself.objectId = conId;
> myself.objectSubId = 0;
> dependDelete(&myself, behavior);
> };
>
>


----------------------------------------------------------------------
----------


>
/*--------------------------------------------------------------------
-----
>  *
>  * depend.c
>  *   random postgres portal and utility support code
>  *
>  * Portions Copyright (c) 1996-2001, PostgreSQL Global Development
Group
>  * Portions Copyright (c) 1994, Regents of the University of
California
>  *
>  *
>  * IDENTIFICATION
>  *   $Header$
>  *
>  * NOTES
>  *   Manage dependencies between varying system objects.
>  *
>
*---------------------------------------------------------------------
----
>  */
>
> #include "postgres.h"
> #include "miscadmin.h"
> #include "access/heapam.h"
> #include "access/genam.h"
> #include "catalog/catname.h"
> #include "catalog/index.h"
> #include "catalog/indexing.h"
> #include "catalog/pg_constraint.h"
> #include "catalog/pg_depend.h"
> #include "catalog/pg_language.h"
> #include "catalog/pg_namespace.h"
> #include "catalog/pg_operator.h"
> #include "catalog/pg_proc.h"
> #include "catalog/pg_type.h"
> #include "commands/comment.h"
> #include "commands/defrem.h"
> #include "commands/tablecmds.h"
> #include "commands/trigger.h"
> #include "commands/view.h"
> #include "nodes/parsenodes.h"
> #include "nodes/pg_list.h"
> #include "nodes/makefuncs.h"
> #include "rewrite/rewriteRemove.h"
> #include "utils/fmgroids.h"
> #include "utils/lsyscache.h"
> #include "utils/syscache.h"
>
> static char *getObjectName(const ObjectAddress *object);
> static char *getObjectType(const ObjectAddress *object);
> static bool  isObjectPinned(const ObjectAddress *object, Relation
rel);
> static bool  isStructureOfPin(const ObjectAddress *object);
>
> /*
>  * Records a requested dependency between 2 objects via their
>  * respective objectAddress.
>  *
>  * It makes the assumption that both objects currently (or will)
>  * exist before the end of the transaction.
>  *
>  * Behaviour, if true tells dependDelete to ignore RESTRICT as
>  * the issued behaviour at the time and cascade to the object
>  * anyway.  The reason for this is sequences generated by SERIAL
>  * and array types.
>  */
> void
> dependCreate(const ObjectAddress *depender,
> const ObjectAddress *dependee,
> bool  behavior)
> {
> if (!IsBootstrapProcessingMode())
> {
> Relation dependDesc;
> TupleDesc tupDesc;
> HeapTuple tup;
> int i;
>
> char nulls[Natts_pg_depend];
> Datum values[Natts_pg_depend];
>
>
> for (i = 0; i < Natts_pg_depend; ++i)
> {
> nulls[i] = ' ';
> values[i] = (Datum) 0;
> }
>
> dependDesc = heap_openr(DependRelationName, RowExclusiveLock);
>
> /* Test to see if the object is pinned (permenant) */
> if (!isObjectPinned(dependee, dependDesc))
> {
> Relation idescs[Num_pg_depend_indices];
> /*
> * Record the Dependency.  Assume it can be added, and
> * doesn't previously exist.  Some items (type creation)
> * may add duplicates.
> */
> values[Anum_pg_depend_classid - 1] =
ObjectIdGetDatum(depender->classId);
> values[Anum_pg_depend_objid - 1] =
ObjectIdGetDatum(depender->objectId);
> values[Anum_pg_depend_objsubid - 1] =
Int32GetDatum(depender->objectSubId);
>
> values[Anum_pg_depend_depclassid - 1] =
ObjectIdGetDatum(dependee->classId);
> values[Anum_pg_depend_depobjid - 1] =
ObjectIdGetDatum(dependee->objectId);
> values[Anum_pg_depend_depobjsubid - 1] =
Int32GetDatum(dependee->objectSubId);
> values[Anum_pg_depend_alwayscascade -1] = BoolGetDatum(behavior);
>
> tupDesc = dependDesc->rd_att;
>
> if (!HeapTupleIsValid(tup = heap_formtuple(tupDesc,
>    values,
>    nulls)))
> elog(ERROR, "DependCreate: heap_formtuple failed");
>
> simple_heap_insert(dependDesc, tup);
>
> /*
> * Keep indices current
> */
> CatalogOpenIndices(Num_pg_depend_indices, Name_pg_depend_indices,
idescs);
> CatalogIndexInsert(idescs, Num_pg_depend_indices, dependDesc, tup);
> CatalogCloseIndices(Num_pg_depend_indices, idescs);
> }
> heap_close(dependDesc, RowExclusiveLock); /* Required? */
> }
> }
>
>
> /*
>  * Drops the interdependencies between the object and it's
>  * children depending on the behavior specified.  RESTRICT or
>  * CASCADE types supported.
>  *
>  * RESTRICT will abort the transaction if other objects depend
>  * on this one.
>  *
>  * CASCADE will drop all objects which depend on the supplied
>  * object address.
>  */
> void
> dependDelete(ObjectAddress *object, int behavior)
> {
>
> Relation rel;
> ScanKeyData dropkey[3];
> HeapTuple tup;
> int dropnkeys = 0;
> SysScanDesc scan;
>
> bool deprem = true;
> ObjectAddress objectCopy;
>
> Assert(behavior == DEPEND_RESTRICT || behavior == DEPEND_CASCADE ||
behavior == DEPEND_IMPLICITONLY);
>
> /*
> * A copy of the object passed in needs to be taken, else we risk
> * it being wiped from memory mid way through the drops.
> */
> objectCopy.classId = object->classId;
> objectCopy.objectId = object->objectId;
> objectCopy.objectSubId  = object->objectSubId;
>
> /* Delete any comments associated with this object */
> DeleteComments(objectCopy.objectId, objectCopy.classId,
objectCopy.objectSubId);
>
> /*
> * Test whether object being dropped is a dependee
> * or not.
> */
> rel = heap_openr(DependRelationName, RowExclusiveLock);
>
> /* If object is pinned dissallow it's removal */
> if (isObjectPinned(&objectCopy, rel))
> elog(ERROR, "Drop Restricted as %s %s is an essential for the
database to function",
> getObjectType(&objectCopy),
> getObjectName(&objectCopy));
>
> while (deprem)
> {
> ScanKeyData key[3];
>
> ObjectAddress foundObject;
> Form_pg_depend foundTup;
> int nkeys = 0;
>
> /* Class Oid */
> Assert(objectCopy.classId != InvalidOid);
> ScanKeyEntryInitialize(&key[nkeys++],
>    0, Anum_pg_depend_depclassid, F_OIDEQ,
>    ObjectIdGetDatum(objectCopy.classId));
>
> /* Object Oid */
> Assert(objectCopy.objectId != InvalidOid);
> ScanKeyEntryInitialize(&key[nkeys++],
>    0, Anum_pg_depend_depobjid, F_OIDEQ,
>    ObjectIdGetDatum(objectCopy.objectId));
>
> /* SubObject Id */
> ScanKeyEntryInitialize(&key[nkeys++],
>    0, Anum_pg_depend_depobjsubid, F_INT4EQ,
>    Int32GetDatum(objectCopy.objectSubId));
>
> scan = systable_beginscan(rel, DependDependeeIndex, true,
>   SnapshotNow, nkeys, key);
>
> /*
> * If no type tuple exists for the given type name, then end the scan
> * and return appropriate information.
> */
> tup = systable_getnext(scan);
> if (!HeapTupleIsValid(tup))
> {
> deprem = false;
> continue;
> }
>
> foundTup = (Form_pg_depend) GETSTRUCT(tup);
>
> /*
> * Lets load up and test the object which depends
> * on the one we want to drop.
> */
> foundObject.classId = foundTup->classid;
> foundObject.objectId = foundTup->objid;
> foundObject.objectSubId = foundTup->objsubid;
>
> systable_endscan(scan);
>
> /*
> * If there are dependencies and behaviour is RESTRICT
> * then drop them all.
> */
> if (behavior == DEPEND_RESTRICT && !foundTup->alwayscascade)
> elog(ERROR, "Drop Restricted as %s %s Depends on %s %s",
> getObjectType(&foundObject),
> getObjectName(&foundObject),
> getObjectType(&objectCopy),
> getObjectName(&objectCopy));
>
> /*
> * When IMPLICITONLY we don't want to cascade or restrict.
> * Simply drop all items implicitly associated with this object.
> */
> if (behavior == DEPEND_IMPLICITONLY && !foundTup->alwayscascade)
> {
> continue;
> }
>
> /* Tell the user */
> if (foundTup->alwayscascade)
> elog(DEBUG1, "Implicit drop of %s %s",
> getObjectType(&foundObject),
> getObjectName(&foundObject));
> else
> elog(NOTICE, "Cascading drop to %s %s",
> getObjectType(&foundObject),
> getObjectName(&foundObject));
>
> /*
> * The below functions are expected to cascade back here by calling
> * dependDelete().  If they don't, a partial cascade can occur
leaving
> * poor relations in place.
> */
> switch (foundObject.classId)
> {
> case RelOid_pg_proc:
> RemoveFunctionById(foundObject.objectId, behavior);
> break;
>
> case RelOid_pg_class:
> {
> HeapTuple relTup;
> char relKind;
> char    *relName;
> char    *schemaName;
>
> relTup = SearchSysCache(RELOID,
> ObjectIdGetDatum(foundObject.objectId),
> 0, 0, 0);
> if (!HeapTupleIsValid(relTup)) {
> elog(ERROR, "dependDelete: Relation %d does not exist",
> foundObject.objectId);
> }
>
> relKind = ((Form_pg_class) GETSTRUCT(relTup))->relkind;
> relName = NameStr(((Form_pg_class) GETSTRUCT(relTup))->relname);
> schemaName = get_namespace_name(((Form_pg_class)
GETSTRUCT(relTup))->relnamespace);
>
> ReleaseSysCache(relTup);
>
> switch(relKind)
> {
> case RELKIND_INDEX:
> /* Drop INDEX
> *
> * Future use will use below once indexes drops are
> * corrected to be selfcontained.  Messages of tuple
> * updates occur if more than a single index is removed
> * during a table drop.
> */
> index_drop(foundObject.objectId, behavior);
> break;
>
> case RELKIND_VIEW:
> RemoveView(makeRangeVar(schemaName, relName), behavior);
> break;
>
> case RELKIND_RELATION:
> case RELKIND_SEQUENCE:
> case RELKIND_TOASTVALUE:
> case RELKIND_SPECIAL:
> RemoveRelation(makeRangeVar(schemaName, relName), behavior);
> break;
> default:
> elog(ERROR, "dependDelete: Unknown relkind %c", relKind);
> }
> break;
> }
>
> case RelOid_pg_type:
> {
> TypeName   *typename;
>
> /* Make a TypeName so we can use standard type lookup machinery */
> typename = makeNode(TypeName);
> typename->names = NIL;
> typename->typeid = foundObject.objectId;
> typename->typmod = -1;
> typename->arrayBounds = NIL;
>
> /* Drop the type */
> RemoveTypeByTypeName(typename, behavior);
>
> break;
> }
> case RelOid_pg_attribute:
> elog(ERROR, "Removing Attribute");
> break;
>
> default:
> /* Can't compare to a 'static' OID */
> if (foundObject.classId == get_relname_relid(AggregateRelationName,
PG_CATALOG_NAMESPACE))
> elog(ERROR, "Removing Aggregate");
>
> else if (foundObject.classId ==
get_relname_relid(ConstraintRelationName, PG_CATALOG_NAMESPACE))
> DropConstraintById(foundObject.objectId, behavior);
>
> else if (foundObject.classId ==
get_relname_relid(LanguageRelationName, PG_CATALOG_NAMESPACE))
> elog(ERROR, "PL Handler");
>
> else if (foundObject.classId ==
get_relname_relid(OperatorRelationName, PG_CATALOG_NAMESPACE))
> RemoveOperatorById(foundObject.objectId, behavior);
>
> else if (foundObject.classId ==
get_relname_relid(RewriteRelationName, PG_CATALOG_NAMESPACE))
> RemoveRewriteRuleById(foundObject.objectId, behavior);
>
> else if (foundObject.classId ==
get_relname_relid(TriggerRelationName, PG_CATALOG_NAMESPACE))
> DropTriggerById(foundObject.objectId, behavior);
>
> else
> elog(ERROR, "getObjectType: Unknown object class %d",
foundObject.classId);
> }
>
> /*
> * We need to assume that cascaded items could potentially
> * remove dependencies we want to as well.  The simplest
> * way to ovoid double deletions (and warnings about tuples
> * being modified twice) is to rescan our list after
> * bumping the command counter.
> */
> CommandCounterIncrement();
> }
>
> /*
> * Now go through the whole thing again looking for our object
> * as the depender so we can drop those dependencies.
> */
>
> /* Class Oid */
> Assert(objectCopy.classId != InvalidOid);
> ScanKeyEntryInitialize(&dropkey[dropnkeys++],
>    0, Anum_pg_depend_classid, F_OIDEQ,
>    ObjectIdGetDatum(objectCopy.classId));
> /* Object Oid */
> Assert(objectCopy.objectId != InvalidOid);
> ScanKeyEntryInitialize(&dropkey[dropnkeys++],
>    0, Anum_pg_depend_objid, F_OIDEQ,
>    ObjectIdGetDatum(objectCopy.objectId));
> /* SubObject Id */
> ScanKeyEntryInitialize(&dropkey[dropnkeys++],
>    0, Anum_pg_depend_objsubid, F_INT4EQ,
>    Int32GetDatum(objectCopy.objectSubId));
>
> scan = systable_beginscan(rel, DependDependerIndex, true,
>   SnapshotNow, dropnkeys, dropkey);
>
> /* Drop dependencies found */
> while (HeapTupleIsValid(tup = systable_getnext(scan))) {
> simple_heap_delete(rel, &tup->t_self);
> }
>
> systable_endscan(scan);
>
> /* Cleanup and get out */
> heap_close(rel, RowExclusiveLock);
> }
>
> /* Delete function to save time */
> void
> dependDeleteTuple(const HeapTuple tup, const Relation relation, int
behavior)
> {
> ObjectAddress myself;
>
> /* Collect the information and call the real delete function */
> myself.classId = RelationGetRelid(relation);
> myself.objectId = tup->t_data->t_oid;
> myself.objectSubId = 0;
>
> dependDelete(&myself, behavior);
> }
>
>
> /* Fetch the Object Name for display */
> static char *
> getObjectName(const ObjectAddress *object)
> {
> char    *name = "Unknown"; /* Unknown to Keep compiler quiet */
>
> switch (object->classId)
> {
> case RelOid_pg_proc:
> {
> /* FUNCTION */
> HeapTuple procTup;
>
> procTup = SearchSysCache(PROCOID,
> ObjectIdGetDatum(object->objectId),
> 0, 0, 0);
> name = NameStr(((Form_pg_proc) GETSTRUCT(procTup))->proname);
>
> ReleaseSysCache(procTup);
> break;
> }
> case RelOid_pg_class:
> {
> /* RELATION */
> HeapTuple relTup;
>
> relTup = SearchSysCache(RELOID,
> ObjectIdGetDatum(object->objectId),
> 0, 0, 0);
> name = NameStr(((Form_pg_class) GETSTRUCT(relTup))->relname);
>
> ReleaseSysCache(relTup);
> break;
> }
> case RelOid_pg_type:
> {
> /* TYPE */
> HeapTuple typeTup;
>
> typeTup = SearchSysCache(TYPEOID,
> ObjectIdGetDatum(object->objectId),
> 0, 0, 0);
> name = NameStr(((Form_pg_type) GETSTRUCT(typeTup))->typname);
>
> ReleaseSysCache(typeTup);
> break;
> }
> case RelOid_pg_attribute:
> /* ATTRIBUTE */
> name = "Unknown";
> break;
>
> default:
> /* Can't compare to a 'static' OID */
> if (object->classId == get_relname_relid(AggregateRelationName,
PG_CATALOG_NAMESPACE))
> /* AGGREGATE */
> name = "Unknown";
>
> else if (object->classId ==
get_relname_relid(ConstraintRelationName, PG_CATALOG_NAMESPACE))
> {
> HeapTuple tup;
> Relation conDesc;
> ScanKeyData skey[1];
> SysScanDesc rcscan;
> int i = 0;
>
> /* CONSTRAINT */
> ScanKeyEntryInitialize(&skey[i++],
>    0, ObjectIdAttributeNumber, F_OIDEQ,
>    ObjectIdGetDatum(object->objectId));
>
> conDesc = heap_openr(ConstraintRelationName, RowExclusiveLock);
> rcscan = systable_beginscan(conDesc, ConstraintOidIndex, true,
> SnapshotNow,
> i, skey);
>
> tup = systable_getnext(rcscan);
>
> if (!HeapTupleIsValid(tup))
> /*
> * elog(ERROR, "Constraint OID %d missing", object->objectId);
> *
> * Due to circular dependencies we simply say we don't know rather
> * than the above line.  This shouldn't happen in any other case
> * than a the circular constraint dependency anyway.
> */
> name = "<Unknown>";
> else
> name = NameStr(((Form_pg_constraint) GETSTRUCT(tup))->conname);
>
> /* Clean up */
> systable_endscan(rcscan);
> }
> else if (object->classId == get_relname_relid(LanguageRelationName,
PG_CATALOG_NAMESPACE))
> {
> /* LANGUAGE */
> HeapTuple langTup;
>
> langTup = SearchSysCache(LANGOID,
> ObjectIdGetDatum(object->objectId),
> 0, 0, 0);
> name = NameStr(((Form_pg_language) GETSTRUCT(langTup))->lanname);
>
> ReleaseSysCache(langTup);
> }
> else if (object->classId == get_relname_relid(OperatorRelationName,
PG_CATALOG_NAMESPACE))
> {
> /* OPERATOR */
> HeapTuple operTup;
>
> operTup = SearchSysCache(OPEROID,
> ObjectIdGetDatum(object->objectId),
> 0, 0, 0);
> name = NameStr(((Form_pg_operator) GETSTRUCT(operTup))->oprname);
>
> ReleaseSysCache(operTup);
> }
> else if (object->classId == get_relname_relid(RewriteRelationName,
PG_CATALOG_NAMESPACE))
> /* RULE */
> name = "Unknown";
>
> else if (object->classId == get_relname_relid(TriggerRelationName,
PG_CATALOG_NAMESPACE))
> /* TRIGGER */
> name = "Unknown";
>
> else
> elog(ERROR, "getObjectType: Unknown object class %d",
object->classId);
> }
>
> return name;
> }
>
>
> /* Fetch the Object Type for display */
> static char *
> getObjectType(const ObjectAddress *object)
> {
> char    *name = "Unknown"; /* Unknown to keep compiler quiet */
>
> switch (object->classId)
> {
> case RelOid_pg_proc:
> name = "Function";
> break;
>
> case RelOid_pg_class:
> {
> HeapTuple relTup;
> char relKind;
>
> relTup = SearchSysCache(RELOID,
> ObjectIdGetDatum(object->objectId),
> 0, 0, 0);
> if (!HeapTupleIsValid(relTup)) {
> elog(ERROR, "getObjectType: Relation %d does not exist",
> object->objectId);
> }
>
> relKind = ((Form_pg_class) GETSTRUCT(relTup))->relkind;
> ReleaseSysCache(relTup);
>
> switch(relKind)
> {
> case RELKIND_INDEX:
> name = "Index";
> break;
> case RELKIND_VIEW:
> name = "View";
> break;
> case RELKIND_RELATION:
> name = "Table";
> break;
> case RELKIND_TOASTVALUE:
> name = "Toast Table";
> break;
> case RELKIND_SEQUENCE:
> name = "Sequence";
> break;
> case RELKIND_SPECIAL:
> name = "Special";
> break;
> default:
> elog(ERROR, "dependDelete: Unknown relkind %c", relKind);
> }
> break;
> }
>
> case RelOid_pg_type:
> name = "Type";
> break;
>
> case RelOid_pg_attribute:
> name = "Table Attribute";
> break;
>
> default:
> /* Can't compare to a 'static' OID */
> if (object->classId == get_relname_relid(AggregateRelationName,
PG_CATALOG_NAMESPACE))
> name = "Aggregate";
>
> else if (object->classId ==
get_relname_relid(ConstraintRelationName, PG_CATALOG_NAMESPACE))
> name = "Constraint";
>
> else if (object->classId == get_relname_relid(LanguageRelationName,
PG_CATALOG_NAMESPACE))
> name = "PL Hander";
>
> else if (object->classId == get_relname_relid(OperatorRelationName,
PG_CATALOG_NAMESPACE))
> name = "Operator";
>
> else if (object->classId == get_relname_relid(RewriteRelationName,
PG_CATALOG_NAMESPACE))
> name = "Rule";
>
> else if (object->classId == get_relname_relid(TriggerRelationName,
PG_CATALOG_NAMESPACE))
> name = "Trigger";
>
> else
> elog(ERROR, "getObjectType: Unknown object class %d",
object->classId);
> }
>
> return name;
> }
>
>
>
> /*
>  * isPinnedDependee()
>  *
>  * Test if the dependee of a found object is a permenant requirement
>  * for basic database functionality.
>  */
> static bool
> isStructureOfPin(const ObjectAddress *object)
> {
> bool ret = false;
>
> if (object->classId == InvalidOid
> && object->objectId == InvalidOid
> && object->objectSubId == 0)
> ret = true;
>
> return(ret);
> }
>
>
> /*
>  * isObjectPinned()
>  *
>  * Test if an object is permenantly required for basic database
functionality
>  */
> static bool
> isObjectPinned(const ObjectAddress *object, Relation rel)
> {
> SysScanDesc scan;
> HeapTuple tup;
> bool ret = false;
> ScanKeyData key[6];
> int nkeys = 0;
>
> /* Pinned in Depender Slot*/
> Assert(object->classId);
> ScanKeyEntryInitialize(&key[nkeys++],
>    0, Anum_pg_depend_classid, F_OIDEQ,
>    ObjectIdGetDatum(object->classId));
>
> Assert(object->objectId);
> ScanKeyEntryInitialize(&key[nkeys++],
>    0, Anum_pg_depend_objid, F_OIDEQ,
>    ObjectIdGetDatum(object->objectId));
>
> ScanKeyEntryInitialize(&key[nkeys++],
>    0, Anum_pg_depend_objsubid, F_INT4EQ,
>    Int32GetDatum(object->objectSubId));
>
>
> scan = systable_beginscan(rel, DependDependerIndex, true,
>   SnapshotNow, nkeys, key);
>
> /*
> * If we find a match, skip the entire process.
> */
> tup = systable_getnext(scan);
> if (HeapTupleIsValid(tup))
> {
> ObjectAddress foundObject;
> Form_pg_depend foundTup;
>
> /*
> * Pinned objects have a dependee ObjectAddress of 0, 0, 0
> * and will only ever have one entry.
> */
> foundTup = (Form_pg_depend) GETSTRUCT(tup);
>
> foundObject.classId = foundTup->depclassid;
> foundObject.objectId = foundTup->depobjid;
> foundObject.objectSubId = foundTup->depobjsubid;
>
> if (isStructureOfPin(&foundObject))
> ret = true;
> }
>
> /* Cleanup and return */
> systable_endscan(scan);
>
> return(ret);
> }
>


----------------------------------------------------------------------
----------


>
/*--------------------------------------------------------------------
-----
>  *
>  * pg_constraint.h
>  *
>  *
>  * Portions Copyright (c) 1996-2001, PostgreSQL Global Development
Group
>  * Portions Copyright (c) 1994, Regents of the University of
California
>  *
>  * NOTES
>  *   the genbki.sh script reads this file and generates .bki
>  *   information from the DATA() statements.
>  *
>
*---------------------------------------------------------------------
----
>  */
> #ifndef PG_CONSTRAINT_H
> #define PG_CONSTRAINT_H
>
> /* ----------------
>  * postgres.h contains the system type definintions and the
>  * CATALOG(), BOOTSTRAP and DATA() sugar words so this file
>  * can be read by both genbki.sh and the C compiler.
>  * ----------------
>  */
>
> /* ----------------
>  * pg_constraint definition.  cpp turns this into
>  * typedef struct FormData_pg_constraint
>  * ----------------
>  */
> CATALOG(pg_constraint)
> {
> /* Oid of the relation this constraint constrains */
> Oid conrelid;
>
> /* Name of this constraint */
> NameData conname;
>
> /*
> * contype is the Constraint Type.
> *
> * Includes 'p'rimary keys, 'u'nique keys, 'f'oreign keys
> * and 'c'heck constraints.
> */
> char contype;
>
> /*
> * Can application of the constraint be deferred until
> * transaction commit?
> */
> bool condeferrable;
>
> /*
> * Is the constraint deferred until transaction commit
> * by default?
> */
> bool condeferred;
>
> /*
> * Foreign key'd relation
> */
> Oid confrelid;
>
> /*
> * confupdtype is the type of update action expected
> */
> char confupdtype;
>
> /*
> * confdeltype is the type of update action expected
> */
> char confdeltype;
>
> /*
> * confmatchtype the match type of the foreign key
> * 'f'ull or 'p'artial
> */
> char confmatchtype;
>
> /*
> * Columns of conrelid that the constraint applies to
> */
> int2 conkey[1];
>
> /*
> * Foreign key'd columns
> */
> int2 confkey[1];
>
> /*
> * Source (text and binary) for check constraints
> */
> text conbin;
> text consrc;
> } FormData_pg_constraint;
>
> /* ----------------
>  * Form_pg_constraint corresponds to a pointer to a tuple with
>  * the format of pg_constraint relation.
>  * ----------------
>  */
> typedef FormData_pg_constraint *Form_pg_constraint;
>
> /* ----------------
>  * compiler constants for pg_constraint
>  * ----------------
>  */
> #define Natts_pg_constraint 13
> #define Anum_pg_constraint_conrelid 1
> #define Anum_pg_constraint_conname 2
> #define Anum_pg_constraint_contype 3
> #define Anum_pg_constraint_condeferrable 4
> #define Anum_pg_constraint_condeferred 5
> #define Anum_pg_constraint_confrelid 6
> #define Anum_pg_constraint_confupdtype 7
> #define Anum_pg_constraint_confdeltype 8
> #define Anum_pg_constraint_confmatchtype 9
> #define Anum_pg_constraint_conkey 10
> #define Anum_pg_constraint_confkey 11
> #define Anum_pg_constraint_conbin 12
> #define Anum_pg_constraint_consrc 13
>
> #define CONSTRAINT_FKEY_RESTRICT 'r'
> #define CONSTRAINT_FKEY_CASCADE 'c'
> #define CONSTRAINT_FKEY_NULL 'n'
> #define CONSTRAINT_FKEY_DEFAULT 'd'
> #define CONSTRAINT_FKEY_NOACTION 'a'
>
> #define CONSTRAINT_FKEY_PARTIAL 'p'
> #define CONSTRAINT_FKEY_FULL 'f'
> #define CONSTRAINT_FKEY_UNSPECIFIED 'u'
>
> #define CONSTRAINT_CHECK 'c'
> #define CONSTRAINT_FOREIGN 'f'
> #define CONSTRAINT_PRIMARY 'p'
> #define CONSTRAINT_UNIQUE 'u'
>
> /*
>  * prototypes for functions in pg_constraint.c
>  */
> extern Oid constraintCreate(Oid relId,
> const char *constraintName,
> char constraintType,
> bool isDeferrable,
> bool isDeferred,
> const AttrNumber *constraintKey,
> int constraintNKeys,
> Oid foreignRelId,
> const AttrNumber *foreignKey,
> int foreignNKeys,
> char foreignUpdateType,
> char foreignDeleteType,
> char foreignMatchType,
> char *conBin,
> char *conSrc);
>
> extern void DropConstraintById(Oid conId, int behavior);
>
> extern char *getConstraintName(Oid relId);
>
> #endif   /* PG_CONSTRAINT_H */
>


----------------------------------------------------------------------
----------


>
/*--------------------------------------------------------------------
-----
>  *
>  * pg_depend.h
>  *   definition of the system "depend" relation (pg_depend)
>  *   along with the relation's initial contents.
>  *
>  *
>  * Portions Copyright (c) 1996-2001, PostgreSQL Global Development
Group
>  * Portions Copyright (c) 1994, Regents of the University of
California
>  *
>  * $Header$
>  *
>  * NOTES
>  *   the genbki.sh script reads this file and generates .bki
> *   information from theDATA() statements.
>  *
>
*---------------------------------------------------------------------
----
>  */
> #ifndef PG_DEPEND_H
> #define PG_DEPEND_H
>
> /* ----------------
>  * postgres.h contains the system type definitions and the
>  * CATALOG(), BOOTSTRAP andDATA() sugar words so this file
>  * can be read by both genbki.sh and the C compiler.
>  * ----------------
>  */
>
> /* ----------------
>  * pg_depend definition.  cpp turns this into
>  * typedef struct FormData_pg_depend
>  * ----------------
>  */
> CATALOG(pg_depend) BKI_PINWRITE BKI_WITHOUT_OIDS
> {
> Oid classid; /* OID of table containing object */
> Oid objid; /* OID of object itself */
> int4 objsubid; /* column number, or 0 if not used */
>
> Oid depclassid; /* OID of table containing dependee object */
> Oid depobjid; /* OID of dependee object itself */
> int4 depobjsubid; /* dependee column number, or 0 if not used */
>
> /*
> * Always cascade to the item, even when the RESTRICT behavior has
been
> * specified.  Used primarily for SERIAL, and ARRAY types.
> */
> bool alwayscascade;
> } FormData_pg_depend;
>
> /* ----------------
>  * Form_pg_depend corresponds to a pointer to a row with
>  * the format of pg_depend relation.
>  * ----------------
>  */
> typedef FormData_pg_depend *Form_pg_depend;
>
> /* ----------------
>  * compiler constants for pg_depend
>  * ----------------
>  */
> #define Natts_pg_depend 7
> #define Anum_pg_depend_classid 1
> #define Anum_pg_depend_objid 2
> #define Anum_pg_depend_objsubid 3
> #define Anum_pg_depend_depclassid 4
> #define Anum_pg_depend_depobjid 5
> #define Anum_pg_depend_depobjsubid 6
> #define Anum_pg_depend_alwayscascade 7
>
> #define DEPEND_RESTRICT 1
> #define DEPEND_CASCADE 2
> #define DEPEND_IMPLICITONLY 3
>
> /*
>  * Dependencies are automatically discovered in the genbki.sh
>  * script by using tha TABLEOID variable located at the top of
>  * the table description files.
>  */
>
>
> typedef struct ObjectAddress
> {
> Oid classId; /* Class Id from pg_class */
> Oid objectId; /* OID of the object */
> int32 objectSubId; /* Subitem within the object (column of table) */
> } ObjectAddress;
>
>
> extern void dependCreate(const ObjectAddress *depender,
> const ObjectAddress *dependee, bool behavior);
> extern void dependDelete(ObjectAddress *object, int behavior);
> extern void dependDeleteTuple(const HeapTuple tup,
>   const Relation relation,
>   int behavior);
>
> #endif   /* PG_DEPEND_H */
>


----------------------------------------------------------------------
----------


> --
> -- Test RESTRICT and CASCADE keywords.
> --
> -- Ensure system types cannot be removed
> DROP TYPE int4 CASCADE;
> ERROR:  Drop Restricted as Type int4 is an essential for the
database to function
> DROP FUNCTION nextval(text) CASCADE;
> ERROR:  Drop Restricted as Function nextval is an essential for the
database to function
> DROP TABLE pg_type CASCADE;
> ERROR:  table "pg_type" is a system table
> -- Function RESTRICT / CASCADE
> DROP FUNCTION widget_in(opaque) RESTRICT; -- fail
> ERROR:  Drop Restricted as Type widget Depends on Function widget_in
> DROP TYPE widget RESTRICT; -- fail
> ERROR:  Drop Restricted as Operator <% Depends on Type widget
> DROP FUNCTION widget_in(opaque) CASCADE;
> NOTICE:  Cascading drop to Type widget
> NOTICE:  Cascading drop to Operator <%
> NOTICE:  Cascading drop to Function pt_in_widget
> DROP TYPE widget RESTRICT; -- doesn't exist
> ERROR:  Type "widget" does not exist
> -- Type RESTRICT / CASCADE
> DROP TYPE city_budget RESTRICT; -- fail
> ERROR:  Drop Restricted as Table city Depends on Type city_budget
> DROP TYPE city_budget CASCADE;
> NOTICE:  Cascading drop to Table city
> DROP TABLE city RESTRICT; -- doesn't exist
> ERROR:  table "city" does not exist
> -- Domain RESTRICT / CASCADE
> DROP DOMAIN ddef1 RESTRICT; -- fail
> ERROR:  Drop Restricted as Table defaulttest Depends on Type ddef1
> DROP DOMAIN ddef1 CASCADE;
> NOTICE:  Cascading drop to Table defaulttest
> DROP TABLE defaulttest RESTRICT; -- doesn't exist
> ERROR:  table "defaulttest" does not exist
> -- Procedural languge RESTRICT / CASCADE
> DROP LANGUAGE plpgsql RESTRICT; -- fail
> ERROR:  Drop Restricted as Function recursion_test Depends on PL
Hander plpgsql
> DROP LANGUAGE plpgsql CASCADE;
> NOTICE:  Cascading drop to Function recursion_test
> NOTICE:  Cascading drop to Function wslot_slotlink_view
> NOTICE:  Cascading drop to Function pslot_slotlink_view
> NOTICE:  Cascading drop to Function pslot_backlink_view
> NOTICE:  Cascading drop to Function tg_slotlink_unset
> NOTICE:  Cascading drop to Function tg_slotlink_set
> NOTICE:  Cascading drop to Function tg_slotlink_a
> NOTICE:  Cascading drop to Trigger Unknown
> NOTICE:  Cascading drop to Trigger Unknown
> NOTICE:  Cascading drop to Trigger Unknown
> NOTICE:  Cascading drop to Trigger Unknown
> NOTICE:  Cascading drop to Trigger Unknown
> NOTICE:  Cascading drop to Function tg_backlink_unset
> NOTICE:  Cascading drop to Function tg_backlink_set
> NOTICE:  Cascading drop to Function tg_backlink_a
> NOTICE:  Cascading drop to Trigger Unknown
> NOTICE:  Cascading drop to Trigger Unknown
> NOTICE:  Cascading drop to Trigger Unknown
> NOTICE:  Cascading drop to Function tg_phone_bu
> NOTICE:  Cascading drop to Trigger Unknown
> NOTICE:  Cascading drop to Function tg_hslot_bu
> NOTICE:  Cascading drop to Trigger Unknown
> NOTICE:  Cascading drop to Function tg_iface_bu
> NOTICE:  Cascading drop to Trigger Unknown
> NOTICE:  Cascading drop to Function tg_pline_bu
> NOTICE:  Cascading drop to Trigger Unknown
> NOTICE:  Cascading drop to Function tg_wslot_bu
> NOTICE:  Cascading drop to Trigger Unknown
> NOTICE:  Cascading drop to Function tg_pslot_bu
> NOTICE:  Cascading drop to Trigger Unknown
> NOTICE:  Cascading drop to Function tg_chkbacklink
> NOTICE:  Cascading drop to Trigger Unknown
> NOTICE:  Cascading drop to Trigger Unknown
> NOTICE:  Cascading drop to Trigger Unknown
> NOTICE:  Cascading drop to Function tg_chkslotlink
> NOTICE:  Cascading drop to Trigger Unknown
> NOTICE:  Cascading drop to Trigger Unknown
> NOTICE:  Cascading drop to Trigger Unknown
> NOTICE:  Cascading drop to Trigger Unknown
> NOTICE:  Cascading drop to Trigger Unknown
> NOTICE:  Cascading drop to Function tg_chkslotname
> NOTICE:  Cascading drop to Trigger Unknown
> NOTICE:  Cascading drop to Trigger Unknown
> NOTICE:  Cascading drop to Trigger Unknown
> NOTICE:  Cascading drop to Trigger Unknown
> NOTICE:  Cascading drop to Trigger Unknown
> NOTICE:  Cascading drop to Function tg_hslot_bd
> NOTICE:  Cascading drop to Trigger Unknown
> NOTICE:  Cascading drop to Function tg_hslot_biu
> NOTICE:  Cascading drop to Trigger Unknown
> NOTICE:  Cascading drop to Function tg_hub_adjustslots
> NOTICE:  Cascading drop to Function tg_hub_a
> NOTICE:  Cascading drop to Trigger Unknown
> NOTICE:  Cascading drop to Function tg_iface_biu
> NOTICE:  Cascading drop to Trigger Unknown
> NOTICE:  Cascading drop to Function tg_system_au
> NOTICE:  Cascading drop to Trigger Unknown
> NOTICE:  Cascading drop to Function tg_pslot_biu
> NOTICE:  Cascading drop to Trigger Unknown
> NOTICE:  Cascading drop to Function tg_pfield_ad
> NOTICE:  Cascading drop to Trigger Unknown
> NOTICE:  Cascading drop to Function tg_pfield_au
> NOTICE:  Cascading drop to Trigger Unknown
> NOTICE:  Cascading drop to Function tg_wslot_biu
> NOTICE:  Cascading drop to Trigger Unknown
> NOTICE:  Cascading drop to Function tg_room_ad
> NOTICE:  Cascading drop to Trigger Unknown
> NOTICE:  Cascading drop to Function tg_room_au
> NOTICE:  Cascading drop to Trigger Unknown
> SELECT recursion_test(2,3);  -- doesn't exist
> ERROR:  Function 'recursion_test(integer, integer)' does not exist
> Unable to identify a function that satisfies the given argument
types
> You may need to add explicit typecasts
> -- Foreign Key RESTRICT / CASCADE
> -- See alter table pktable and fktable tests
>


----------------------------------------------------------------------
----------


>
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