Thread: Create function problem
*Hello I have a little question
In order to know the names and data types of the table "mil_cien_diez"
from the schema "public" I run the next 'SELECT' but when I try to
create a SQL function and after it I run it, I receive an empty row. Can
you see the problem ??*
/mydb=> SELECT c.column_name, c.data_type, e.data_type AS element_type
mydb-> FROM information_schema.columns c LEFT JOIN
information_schema.element_types e
mydb-> ON ((c.table_catalog, c.table_schema, c.table_name, 'TABLE',
c.dtd_identifier)
mydb-> = (e.object_catalog, e.object_schema, e.object_name,
e.object_type, e.array_type_identifier))
mydb-> WHERE c.table_schema = 'public' AND c.table_name = 'mil_cien_diez'
mydb-> ORDER BY c.ordinal_position;
column_name | data_type | element_type
-------------+-----------+--------------
miles | smallint |
cientos | smallint |
decenas | smallint |
(3 rows)
/
*The "CREATE FUNCTION" code is the next :*
/mydb=> CREATE OR REPLACE FUNCTION f_describe_tables (text, text
mydb(> ,OUT text, OUT text, OUT text) as
mydb-> $$ SELECT c.column_name, c.data_type, e.data_type AS element_type
mydb$> FROM information_schema.columns c LEFT JOIN
information_schema.element_types e
mydb$> ON ((c.table_catalog, c.table_schema, c.table_name, 'TABLE',
c.dtd_identifier)
mydb$> = (e.object_catalog, e.object_schema, e.object_name,
e.object_type, e.array_type_identifier))
mydb$> WHERE c.table_schema = $1 AND c.table_name = $2
mydb$> ORDER BY c.ordinal_position;
mydb$> $$ LANGUAGE SQL;
CREATE FUNCTION
mydb=> SELECT * FROM f_describe_tables('pubilc', 'mil_cien_diez');
column1 | column2 | column3
---------+---------+---------
| |
(1 row)
/
*Thank you,
Gustavo
*
On Fri, Aug 04, 2006 at 01:51:19AM +0300, gustavo halperin wrote:
> In order to know the names and data types of the table "mil_cien_diez"
> from the schema "public" I run the next 'SELECT' but when I try to
> create a SQL function and after it I run it, I receive an empty row. Can
> you see the problem ??*
[...]
> mydb=> SELECT * FROM f_describe_tables('pubilc', 'mil_cien_diez');
'public' looks misspelled. Does the query work if you change it?
--
Michael Fuhr
Ron St-Pierre wrote:
> Check your spelling of public:
> SELECT * FROM f_describe_tables('pubilc', 'mil_cien_diez');
>
> Ron
>
*OK thank you, you right, but after write "public" I receive again an
empty row, Why??.
By the way I wrote a short function:*
/mydb=> SELECT c.column_name, c.data_type
mydb-> FROM information_schema.columns c
mydb-> WHERE c.table_schema = 'public' AND c.table_name = 'mil_cien_diez';
column_name | data_type
-------------+-----------
miles | smallint
cientos | smallint
decenas | smallint
(3 rows)
mydb=> CREATE OR REPLACE FUNCTION f_describe_tables (v_tbl_scm text,
v_tbl_name text,
mydb(> OUT text, OUT text) as
mydb-> $$ SELECT c.column_name, c.data_type
mydb$> FROM information_schema.columns c
mydb$> WHERE c.table_schema = 'v_tbl_schm' AND c.table_name = 'v_tbl_name'
mydb$> $$ LANGUAGE SQL;
CREATE FUNCTION
mydb=> SELECT * FROM f_describe_tables('public', 'mil_cien_diez');
column1 | column2
---------+---------
|
(1 row)
/
On Fri, Aug 04, 2006 at 06:16:41AM +0300, gustavo halperin wrote: > *OK thank you, you right, but after write "public" I receive again an > empty row, Why??. [...] > mydb=> CREATE OR REPLACE FUNCTION f_describe_tables (v_tbl_scm text, > v_tbl_name text, > mydb(> OUT text, OUT text) as > mydb-> $$ SELECT c.column_name, c.data_type > mydb$> FROM information_schema.columns c > mydb$> WHERE c.table_schema = 'v_tbl_schm' AND c.table_name = 'v_tbl_name' > mydb$> $$ LANGUAGE SQL; You've hardcoded the strings 'v_tbl_schm' and 'v_tbl_name' instead of using the function's arguments. I don't think SQL functions support named arguments so you'll need to use $1 and $2. You'll also need to use "RETURNS SETOF record" if you want to return more than one row. -- Michael Fuhr
[Please copy the mailing list on replies so others can contribute to and learn from the discussion.] On Fri, Aug 04, 2006 at 11:20:55AM +0300, gustavo halperin wrote: > Michael Fuhr wrote: > >You've hardcoded the strings 'v_tbl_schm' and 'v_tbl_name' instead > >of using the function's arguments. I don't think SQL functions > >support named arguments so you'll need to use $1 and $2. You'll > >also need to use "RETURNS SETOF record" if you want to return more > >than one row. > > > *OK thank you, I did it. But I receive actually one row, same as you > say, and I need a set of rows for two columns. I don't know how to use > 'RETURNS SETOF' for two columns, This is possible ??, see the function > below:* > /CREATE OR REPLACE FUNCTION f_describe_tables (text, text > OUT text, OUT text) as -- How to use RETURNS SETOF with *two text columns*?? > $$ SELECT c.column_name, c.data_type > FROM information_schema.columns c > WHERE c.table_schema = $1 AND c.table_name = $2 > $$ LANGUAGE SQL;/ Since the function has OUT parameters you can use "RETURNS SETOF record" like this: CREATE FUNCTION funcname(<params>) RETURNS SETOF record AS $$ <body> $$ LANGUAGE SQL; -- Michael Fuhr
Michael Fuhr wrote:
> [Please copy the mailing list on replies so others can contribute
> to and learn from the discussion.]
>
> On Fri, Aug 04, 2006 at 11:20:55AM +0300, gustavo halperin wrote:
>
>> Michael Fuhr wrote:
>>
>>> You've hardcoded the strings 'v_tbl_schm' and 'v_tbl_name' instead
>>> of using the function's arguments. I don't think SQL functions
>>> support named arguments so you'll need to use $1 and $2. You'll
>>> also need to use "RETURNS SETOF record" if you want to return more
>>> than one row.
>>>
>>>
>> *OK thank you, I did it. But I receive actually one row, same as you
>> say, and I need a set of rows for two columns. I don't know how to use
>> 'RETURNS SETOF' for two columns, This is possible ??, see the function
>> below:*
>> /CREATE OR REPLACE FUNCTION f_describe_tables (text, text
>> OUT text, OUT text) as -- How to use RETURNS SETOF with *two text columns*??
>> $$ SELECT c.column_name, c.data_type
>> FROM information_schema.columns c
>> WHERE c.table_schema = $1 AND c.table_name = $2
>> $$ LANGUAGE SQL;/
>>
>
> Since the function has OUT parameters you can use "RETURNS SETOF record"
> like this:
>
> CREATE FUNCTION funcname(<params>) RETURNS SETOF record AS $$
> <body>
> $$ LANGUAGE SQL
What do you mean with the word "record", can you give an example of how
this "record" looks for two columns ?
Thank you,
Gustavo
On Fri, Aug 04, 2006 at 06:44:16PM +0300, gustavo halperin wrote: > Michael Fuhr wrote: > >Since the function has OUT parameters you can use "RETURNS SETOF record" > >like this: > > > >CREATE FUNCTION funcname(<params>) RETURNS SETOF record AS $$ > ><body> > >$$ LANGUAGE SQL > > What do you mean with the word "record", can you give an example of how > this "record" looks for two columns ? "record" means the literal word "record". Example: CREATE FUNCTION show_tables(OUT schema_name text, OUT table_name text) RETURNS SETOF record AS $$ SELECT table_schema, table_name FROM information_schema.tables; $$ LANGUAGE sql; SELECT * FROM show_tables(); -- Michael Fuhr
Michael Fuhr wrote:
> On Fri, Aug 04, 2006 at 06:44:16PM +0300, gustavo halperin wrote:
>
>> Michael Fuhr wrote:
>>
>>> Since the function has OUT parameters you can use "RETURNS SETOF record"
>>> like this:
>>>
>>> CREATE FUNCTION funcname(<params>) RETURNS SETOF record AS $$
>>> <body>
>>> $$ LANGUAGE SQL
>>>
>> What do you mean with the word "record", can you give an example of how
>> this "record" looks for two columns ?
>>
>
> "record" means the literal word "record". Example:
>
> CREATE FUNCTION show_tables(OUT schema_name text, OUT table_name text)
> RETURNS SETOF record AS $$
> SELECT table_schema, table_name
> FROM information_schema.tables;
> $$ LANGUAGE sql;
>
> SELECT * FROM show_tables()
Thank you, IS WORK, Thank you very much for your help.
Gustavo