问题
I have a trigger, but I need to associate with all tables of the my postgres. Is there a command like this below?
CREATE TRIGGER delete_data_alldb
BEFORE DELETE
ON ALL DATABASE
FOR EACH ROW
EXECUTE PROCEDURE delete_data();
回答1:
Well there is no database-wide trigger creation but for all such bulk-admin-operations you could use PostgreSQL system tables to generate queries for you instead of writing them by hand. In this case you could run:
SELECT
'CREATE TRIGGER '
|| tab_name
|| ' BEFORE DELETE ON ALL DATABASE FOR EACH ROW EXECUTE PROCEDURE delete_data();' AS trigger_creation_query
FROM (
SELECT
quote_ident(table_schema) || '.' || quote_ident(table_name) as tab_name
FROM
information_schema.tables
WHERE
table_schema NOT IN ('pg_catalog', 'information_schema')
AND table_schema NOT LIKE 'pg_toast%'
) tablist;
This will get you set of strings which are SQL commands like:
CREATE TRIGGER schema1.table1 BEFORE DELETE ON ALL DATABASE FOR EACH ROW EXECUTE PROCEDURE delete_data();
CREATE TRIGGER schema1.table2 BEFORE DELETE ON ALL DATABASE FOR EACH ROW EXECUTE PROCEDURE delete_data();
CREATE TRIGGER schema1.table3 BEFORE DELETE ON ALL DATABASE FOR EACH ROW EXECUTE PROCEDURE delete_data();
CREATE TRIGGER schema2.table1 BEFORE DELETE ON ALL DATABASE FOR EACH ROW EXECUTE PROCEDURE delete_data();
CREATE TRIGGER schema2."TABLE2" BEFORE DELETE ON ALL DATABASE FOR EACH ROW EXECUTE PROCEDURE delete_data();
...
etc
You just need to run them at once (either by psql
or pgAdmin).
Now some explanation:
- I select names of tables in my database using
information_schema.tables
system table. Because there are data of literally all tables, remember to excludepg_catalog
andinformation_schema
schemas and toast tables from yourselect
. - I use
quote_ident(text)
function which will put string inside double quote signs (""
) if necessary (ie. names with spaces or capital letters require that). - When I have list of tables names I just concatenate them with some static strings to get my SQL commands.
- I write that command using sub-query because I want you to get better idea of what's going on here. You may write a single query by putting
quote_ident(table_schema) || '.' || quote_ident(table_name)
in place oftab_name
.
来源:https://stackoverflow.com/questions/29675347/how-to-create-trigger-for-all-table-in-postgresql