I can't figure out how to access variables inside my plpgsql function. I'm using postgres 9.5 under Cygwin.
functions.sql
-- this works fine
\echo Recreate = :oktodrop
CREATE OR REPLACE FUNCTION drop_table(TEXT) RETURNS VOID AS
$$
BEGIN
IF EXISTS ( SELECT * FROM information_schema.tables WHERE table_name = $1 ) THEN
-- syntax error here:
IF (:oktodrop == 1 ) THEN
DROP TABLE $1;
END IF;
END IF;
END;
$$
language 'plpgsql';
psql.exe -v oktodrop=1 -f functions.sql
Password:
Recreate = 1
psql:functions.sql:13: ERROR: syntax error at or near ":"
LINE 5: IF (:oktodrop == 1 ) THEN
^
Perhaps I've oversimplified your task (feel free to tell me if that's the case), but why not create the function like this:
CREATE OR REPLACE FUNCTION drop_table(tablename TEXT, oktodrop integer)
RETURNS text AS
$$
DECLARE
result text;
BEGIN
IF EXISTS ( SELECT * FROM information_schema.tables WHERE table_name = tablename ) THEN
IF (oktodrop = 1 ) THEN
execute 'DROP TABLE ' || tablename;
result := 'Dropped';
ELSE
result := 'Not Okay';
END IF;
ELSE
result := 'No such table';
END IF;
return result;
END;
$$
language 'plpgsql';
Then the implementation would be:
select drop_table('foo', 1);
I should also caution that because you have not specified the table_schema field, it's conceivable that your target table exists in another schema, and the actual drop command will fail because it doesn't exist in the default schema.
Related
I have a function that takes 3 parameters: huc, id_list, and email.
CREATE OR REPLACE FUNCTION my_app.job_batch(
huc text,
input_list text[],
email text
) RETURNS VOID AS
$$
DECLARE
id text;
BEGIN
FOREACH id IN ARRAY input_list LOOP
EXECUTE 'SELECT * FROM my_app.my_funct(
' || huc || '::text,
' || id || '::text,
' || email || '::text)';
END LOOP;
END;
$$
LANGUAGE plpgsql;
When I try to run the function however, it throws an error: ERROR: column "myhu4" does not exist
SELECT * FROM spg_app.append_spg_job_batch('MYHUC4', array['1021', '1025','1026','1027','0701','0702','0703','0708','0709'], 'myemail#gmail.com');
Why is it referring to myhuc4 as a column and why is displaying it in lower case. Is my syntax below to run the function with those 3 parameters incorrect? Note: If I run the below hardcoded version, it runs fine:
DO $$
DECLARE
id_list text[] := array['1021', '1025','1026','1027','0701','0702','0703','0708','0709'];
id text;
BEGIN
FOREACH id in ARRAY id_list LOOP
EXECUTE 'SELECT * FROM my_app.my_funct(
''MYHU4''::text,
' || id || '::text,
''myemail#gmail.com''::text)'
END LOOP;
END;
$$
LANGUAGE plpgsql;
I suggest to use parameters instead of bad practice of stitching strings, as follows:
CREATE OR REPLACE FUNCTION my_app.job_batch(
huc text,
input_list text[],
email text
) RETURNS VOID AS
$$
DECLARE
id text;
BEGIN
FOREACH id IN ARRAY input_list LOOP
execute format ('SELECT * FROM my_app.my_funct($1, $2, $3)')
using huc, id, email;
END LOOP;
END;
$$
LANGUAGE plpgsql;
as shown in official docs https://www.postgresql.org/docs/current/plpgsql-statements.html#PLPGSQL-STATEMENTS-EXECUTING-DYN
I checked all related questions on SO but none helped in my case.
I have 2 loops(outside for the tables and inside for the columns). Tables are represented by 'r', and columns by 'm'. While being inside the 'm' loop which is supposed to send column values to the to-be-created trigger function. When I try to use 'NEW.m' (with trying many different formatting attempts) compiler always gives error.
Can you kindly advice on it please? Br
FOR r IN SELECT table_name FROM information_schema.tables LOOP
FOR m IN SELECT column_name FROM information_schema.columns WHERE (table_name = r.table_name ) LOOP
function_name := 'dictionary_functions_foreach_trigger';
EXECUTE format('CREATE OR REPLACE FUNCTION %s()
RETURNS trigger AS
$BODY$
DECLARE
BEGIN
IF NEW.m IS NOT NULL AND NEW.m IN (SELECT key FROM tableX.tableX_key)
THEN RETURN NEW;
END IF;
END;
$BODY$
LANGUAGE plpgsql VOLATILE
COST 100;
ALTER FUNCTION %s()
OWNER TO mydb;',function_name, function_name);
EXECUTE 'CREATE TRIGGER ' || function_name || ' BEFORE INSERT OR UPDATE ON ' || belonging_to_schema || '.' || r.table_name || ' FOR EACH ROW EXECUTE PROCEDURE ' || function_name || '();';
----Trigger Functions after edit-
EXECUTE format(
'CREATE OR REPLACE FUNCTION %s()
RETURNS trigger AS
$BODY$
DECLARE
insideIs text := %s ;
BEGIN
FOR %s IN 0..(TG_NARGS-1) LOOP
IF %I= TG_ARGV[%s]
THEN insideIs := %s ;
END IF;
END LOOP;
IF NEW.%I IS NOT NULL AND (insideIs =%s) AND NEW.%I IN (SELECT key FROM tableX.tableX_key)
THEN RETURN NEW;
ELSE RETURN OLD;
END IF;
END;
$BODY$
LANGUAGE plpgsql VOLATILE
COST 100;
ALTER FUNCTION %s()
OWNER TO mydb;' , function_name, 'notInside', 'i' , m.column_name, 'i' , 'ok', m.column_name, 'ok', m.column_name ,function_name);
You need to use another placeholder for the column name, they way you have written it, the column name "m" is hardcoded in the function.
You also don't really need the outer loop, as the table_name is also available in information_schema.columns.
Your trigger would also fail with a runtime error if the condition is not true as you don't have a return in that case. If you want to abort the statement, use return null;
You should also use format() for the create trigger statement.
FOR m IN SELECT table_schema, table_name, column_name
FROM information_schema.columns
WHERE table_name in (...)
LOOP
function_name := 'dictionary_functions_foreach_trigger';
EXECUTE format('CREATE OR REPLACE FUNCTION %I()
RETURNS trigger AS
$BODY$
DECLARE
BEGIN
IF NEW.%I IS NOT NULL AND NEW.%I IN (SELECT key FROM tableX.tableX_key) THEN
RETURN NEW;
END IF;
RETURN null; --<< you need some kind of return here!
END;
$BODY$
LANGUAGE plpgsql VOLATILE
COST 100;
ALTER FUNCTION %s()
OWNER TO mydb;', function_name, m.column_name, m.column_name, function_name, function_name);
EXECUTE format('CREATE TRIGGER %I BEFORE INSERT OR UPDATE ON %I.%I FOR EACH ROW EXECUTE PROCEDURE %I()',
function_name, m.table_schema, m.table_name, function_name);
END LOOP;
Online example
I am a newbie wrt functions and I am struggling with using the name of a table in the function body. I get an error "SQL Error [42703]: ERROR: column "tname" does not exist" when I call the function using
select "JsonToView"('data_import.import_360xero_report');
My code is below
create or replace
function data_import."JsonToView"(tname text) returns numeric
language plpgsql
as $function$
begin
do
$$
declare
l_keys text;
begin
drop view if exists v_json_view cascade;
select
string_agg(distinct format('import_data ->> %L as %I', jkey, jkey), ', ')
into
l_keys
from
import_360xero_report,
json_object_keys(import_data) as t(jkey);
execute 'create view v_json_view as select ' || l_keys || ' from ' || tname;
end;
$$;
return 0;
end $function$ ;
I have modified the code and the second create view query works with the table name but the first one does not.
Below if my modified code
create or replace
function data_import."JsonToView"(tname text) returns numeric
language plpgsql
as $function$
declare
l_keys text;
begin
drop view if exists v_json_view cascade;
execute $a$select
string_agg(distinct format('import_data ->> %L as %I', jkey, jkey), ', ')
into
l_keys
from $a$ ||
tname || $b$,
json_object_keys(import_data) as t(jkey)$b$;
execute 'create view v_json_view as select ' || l_keys || ' from ' || tname;
return 0;
end $function$ ;
The error I am getting is
SQL Error [0A000]: ERROR: EXECUTE of SELECT ... INTO is not implemented
Hint: You might want to use EXECUTE ... INTO or EXECUTE CREATE TABLE ... AS instead.
Where: PL/pgSQL function "JsonToView"(text) line 10 at EXECUTE
The problem is the superfluous nested DO statement.
The variable tname exists only in the scope of the function, not in the nested DO statement. DO is an SQL statement, not a PL/pgSQL statement, and there are no variables in SQL. Also, DO does not allow parameters.
Get rid of the DO and you will be fine.
I have a Postgresql database with many tables, some of these tables have a column called 'description'. Some of these descriptions contain the word 'dog'. How can I print the tables names for the tables that have the string 'dog' anywhere in the column 'description', case insensitive?
I tried with a script, but it is failing with the error
$$ LANGUAGE plpgsql
ERROR: syntax error at or near "END"
LINE 16: END LOOP;**
This is the script:
CREATE OR REPLACE FUNCTION findAllDogsInDescription()
RETURNS VOID
AS $$
DECLARE
my_row RECORD;
a int;
i boolean;
BEGIN
FOR my_row IN
SELECT table_name from information_schema.columns where column_name = 'description'
LOOP
execute 'select count(*) from ' || my_row.table_name || ' where description ilike ''%dog%'' ' into i;
if (i > 0) THEN
raise 'Found a dog in the description of the table %', my_row.table_name;
END IF
END LOOP;
END;
$$ LANGUAGE plpgsql;
SELECT findAllDogsInDescription();
It's a simple syntax error. You just need a ; after the END IF. And you need to use a (which is an int) instead of i in the execute ... into statement.
CREATE OR REPLACE FUNCTION findAllDogsInDescription()
RETURNS VOID
AS $$
DECLARE
my_row RECORD;
a int;
i boolean;
BEGIN
FOR my_row IN
SELECT table_name from information_schema.columns where column_name = 'description'
LOOP
execute 'select count(*) from ' || my_row.table_name || ' where description ilike ''%dog%'' ' into a;
if (a > 0) THEN
raise 'Found a dog in the description of the table %', my_row.table_name;
END IF;
END LOOP;
END;
$$ LANGUAGE plpgsql;
SELECT findAllDogsInDescription();
I'm trying to implement a generic trigger procedure to enable a sort a versioning scheme on tables. Tables all have version and current fields. On updates, in some situations based on a condition, i want to create a new version of a row instead of updating the old one. I'm having trouble getting the default value for the primary key field (always id).
Here's what i've done:
CREATE FUNCTION version_trigger() RETURNS trigger AS $$
DECLARE
id_default text;
id_value text;
BEGIN
IF version_condition() THEN
old.current = false;
-- I can read the default value
SELECT column_default INTO id_default
FROM information_schema.columns
WHERE table_name = TG_TABLE_NAME AND column_name = 'id';
-- THIS DOESN'T WORK!
EXECUTE 'SELECT $1' INTO id_value USING id_default;
new.id = id_value;
EXECUTE 'INSERT INTO ' || quote_ident(TG_TABLE_NAME) || ' SELECT ($1).*' USING new;
RETURN old;
END IF;
-- regular UPDATE
RETURN new;
END
$$ LANGUAGE plpgsql;
I'm just missing the step where i read the default value for the id (it's just a nextval() call). Can anyone help out on this?
Thanks in advance!
You cannot use a placeholder for expressions.
If DEFAULT doesn't have any reference to record data, then you can use EXECUTE statement, but little bit different
postgres=# DO $$
DECLARE x text; y text;
BEGIN
x := (SELECT column_default
FROM information_schema.columns
WHERE table_name = 'omega' AND column_name = 'a');
EXECUTE 'SELECT ' || x INTO y;
RAISE NOTICE '%', y;
END;
$$;
NOTICE: 2
DO