Hello! :)
(Sorry for my english. But if i wrote in portuguese, you wouldn't
understand nothing. :])
I found it's the right place to post this. I'm a newcomer in these
lists. I hope i did it right. :]
<BOREDOM>
When i started using SQL, i started with mSQL. I developed a lot
of useful apps for me and my job with C, mainly because i loved it's
elegant, simple api. But for a large project i'm doing in these days, i
thought is was not enough, because it felt a lot of features i started to
need, like security and subselects. (and it's not free :))
So after looking at the options, choose to start again with
postgres. It offered everything that i needed, and the documentation is
really good (remember me to thank the one who wrote'em).
But for my little apps, i needed to start porting them to libpq.
After looking at pq's syntax, i found it was better to write a bridge
between the mSQL api and libpq. I found that rewriting the libmsql.a
routines that calls libpq would made things much easier. I guess the
results are quite good right now.
</BOREDOM>
Ok. Lets' summarize it:
mpgsql.c is the bridge. Acting as a wrapper, it's really good,
since i could run mSQL. But it's not accurate. Some highlights:
CONS:
* It's not well documented
(this post is it's first documentation attempt, in fact);
* It doesn't handle field types correctly. I plan to fix it,
if people start doing feedbacks;
* It's limited to 10 simultaneous connections. I plan to enhance
this, i'm just figuring out;
* I'd like to make it reentrant/thread safe, although i don't
think this could be done without changing the API structure;
* Error Management should be better. This is my first priority
now;
* Some calls are just empty implementations.
PROS:
* the mSQL Monitor runs Okay. :]
* It's really cool. :)
* Make mSQL-made applications compatible with postgresql just by
changing link options.
* Uses postgreSQL. :]
* the mSQL API it's far easier to use and understand than libpq.
Consider this example:
#include "msql.h"
void main(int argc, char **argv, char **envp) {
int sid;
sid = msqlConnect(NULL); /* Connects via unix socket */
if (sid >= 0) {
m_result *rlt;
m_row *row;
msqlSelectDB(sid, "hosts");
if (msqlQuery(sid, "select host_id from hosts")) {
rlt = msqlStoreResult();
while (row = (m_row*)msqlFetchRow(rlt))
printf("hostid: %s\n", row[0]);
msqlFreeResult(rlt);
}
msqlClose(sid);
}
}
I enclose mpgsql.c inside. I'd like to maintain it, and (maybe, am
i dreaming) make it as part of the pgsql distribution. I guess it doesn't
depends on me, but mainly on it's acceptance by its users.
Hm... i forgot: you'll need a msql.h copy, since it's copyrighted
by Hughes Technologies Pty Ltd. If you haven't it yes, fetch one
from www.hughes.com.au.
I would like to catch users ideas. My next goal is to add better
error handling, and to make it better documented, and try to let relshow
run through it. :)
done. Aldrin Leal <aldrin@americasnet.com>
#include <time.h>
#include <string.h>
#include <stdlib.h>
#include "msql.h"
#include "libpq-fe.h"
#define HNDMAX 10
PGconn *PGh[HNDMAX] = {
NULL, NULL, NULL, NULL, NULL,
NULL, NULL, NULL, NULL, NULL
};
#define E_NOHANDLERS 0
char *msqlErrors[] = {
"Out of database handlers."
};
char msqlErrMsg[BUFSIZ], *tfrom = "dunno";
PGresult *queryres = NULL;
int msqlConnect (char *host) {
int count;
for (count = 0; count < HNDMAX; count++)
if (PGh[count] == NULL) break;
if (count == HNDMAX) {
strncpy(msqlErrMsg, msqlErrors[E_NOHANDLERS], BUFSIZ);
return -1;
}
PGh[count] = malloc(sizeof (PGconn));
PGh[count]->pghost = host ? strdup(host) : NULL;
return count;
}
int msqlSelectDB(int handle, char *dbname) {
char *options = calloc(1, BUFSIZ);
char *e = getenv("PG_OPTIONS");
if (e == NULL)
e = "";
if (PGh[handle]->pghost) {
strcat(options, "host=");
strncat(options, PGh[handle]->pghost, BUFSIZ);
strncat(options, " ", BUFSIZ);
free(PGh[handle]->pghost);
PGh[handle]->pghost = NULL;
}
strncat(options, "dbname=", BUFSIZ);
strncat(options, dbname, BUFSIZ);
strncat(options, " ", BUFSIZ);
strncat(options, e, BUFSIZ);
free(PGh[handle]);
PGh[handle] = PQconnectdb(options);
free(options);
strncpy(msqlErrMsg, PQerrorMessage(PGh[handle]), BUFSIZ);
return (PQstatus(PGh[handle]) == CONNECTION_BAD ? -1 : 0);
}
int msqlQuery(int handle, char *query) {
char *tq = strdup(query);
char *p = tq;
PGresult *res;
PGconn *conn = PGh[handle];
ExecStatusType rcode;
res = PQexec(conn, p);
rcode = PQresultStatus(res);
if (rcode == PGRES_TUPLES_OK) {
queryres = res;
return PQntuples(res);
} else if (rcode == PGRES_FATAL_ERROR || rcode == PGRES_NONFATAL_ERROR) {
PQclear(res);
queryres = NULL;
return -1;
} else {
PQclear(res);
queryres = NULL;
return 0;
}
}
int msqlCreateDB (int a, char*b) {
char tbuf[BUFSIZ];
sprintf(tbuf, "create database %s", b);
return msqlQuery(a, tbuf) >= 0 ? 0 : -1;
}
int msqlDropDB (int a, char* b) {
char tbuf[BUFSIZ];
sprintf(tbuf, "drop database %s", b);
return msqlQuery(a, tbuf) >= 0 ? 0 : -1;
}
int msqlShutdown(int a) {
}
int msqlGetProtoInfo(void) {
}
int msqlReloadAcls(int a) {
}
char *msqlGetServerInfo(void) {
}
char *msqlGetHostInfo(void) {
}
char *msqlUnixTimeToDate(time_t date) {
}
char *msqlUnixTimeToTime(time_t time) {
}
void msqlClose(int a) {
PQfinish(PGh[a]);
PGh[a] = NULL;
if (queryres) {
free(queryres);
queryres = NULL;
}
}
void msqlDataSeek(m_result *result, int count) {
int c;
result->cursor = result->queryData;
for (c = 1; c < count; c++)
if (result->cursor->next)
result->cursor = result->cursor->next;
}
void msqlFieldSeek(m_result *result, int count) {
int c;
result->fieldCursor = result->fieldData;
for (c = 1; c < count; c++)
if (result->fieldCursor->next)
result->fieldCursor = result->fieldCursor->next;
}
void msqlFreeResult(m_result *result) {
if (result) {
/* Clears fields */
free(result->fieldData);
result->cursor = result->queryData;
while (result->cursor) {
int c;
m_row m = result->cursor->data;
for (c = 0; m[c]; c++)
free(m[c]);
result->cursor = result->cursor->next;
}
free(result->queryData);
free(result);
}
}
m_row msqlFetchRow(m_result *row) {
m_data *r = row->cursor;
if (r) {
row->cursor = row->cursor->next;
return (m_row)r->data;
}
return (m_row)NULL;
}
m_seq *msqlGetSequenceInfo(int a, char *b) {
}
m_field *msqlFetchField (m_result *mr) {
m_field *m = (m_field*)mr->fieldCursor;
if (m) {
mr->fieldCursor = mr->fieldCursor->next;
return m;
}
return NULL;
}
m_result *msqlListDBs(int a) {
m_result *m;
if (msqlQuery(a, "select datname from pg_database") > 0) {
m = msqlStoreResult();
return m;
} else return NULL;
}
m_result *msqlListTables(int a) {
m_result *m;
char tbuf[BUFSIZ];
sprintf(tbuf, "select relname from pg_class where relkind='r' and relowner=%d", getuid());
if (msqlQuery(a, tbuf) > 0) {
m = msqlStoreResult();
return m;
} else return NULL;
}
m_result *msqlListFields(int a, char *b) {
}
m_result *msqlListIndex(int a, char *b, char *c) {
m_result *m;
char tbuf[BUFSIZ];
sprintf(tbuf, "select relname from pg_class where relkind='i' and relowner=%d", getuid());
if (msqlQuery(a, tbuf) > 0) {
m = msqlStoreResult();
return m;
} else return NULL;
}
m_result *msqlStoreResult(void) {
if (queryres) {
m_result *mr = malloc(sizeof(m_result));
m_fdata *mf;
m_data *md;
int count;
mr->queryData = mr->cursor = NULL;
mr->numRows = PQntuples(queryres);
mr->numFields = PQnfields(queryres);
mf = calloc(PQnfields(queryres), sizeof(m_fdata));
for (count = 0; count < PQnfields(queryres); count++) {
(m_fdata*)(mf+count)->field.name = strdup(PQfname(queryres, count));
(m_fdata*)(mf+count)->field.table = tfrom;
(m_fdata*)(mf+count)->field.type = CHAR_TYPE;
(m_fdata*)(mf+count)->field.length = PQfsize(queryres, count);
(m_fdata*)(mf+count)->next = (m_fdata*)(mf+count+1);
}
(m_fdata*)(mf+count-1)->next = NULL;
md = calloc(PQntuples(queryres), sizeof(m_data));
for (count = 0; count < PQntuples(queryres); count++) {
m_row rows = calloc(PQnfields(queryres)*sizeof(m_row)+1, 1);
int c;
for (c = 0; c < PQnfields(queryres); c++) {
rows[c] = strdup(PQgetvalue(queryres, count, c));
}
(m_data*)(md+count)->data = rows;
(m_data*)(md+count)->width = PQnfields(queryres);
(m_data*)(md+count)->next = (m_data*)(md+count+1);
}
(m_data*)(md+count-1)->next = NULL;
mr->queryData = mr->cursor = md;
mr->fieldCursor = mr->fieldData = mf;
return mr;
} else return NULL;
}
time_t msqlDateToUnixTime(char *a) {
}
time_t msqlTimeToUnixTime(char *b) {
}
char *msql_tmpnam(void) {
return tmpnam("/tmp/msql.XXXXXX");
}
int msqlLoadConfigFile(char *a) {
}
