DO

Synopsis

Use the DO statement to execute an anonymous code block, or in other words, a transient anonymous function in a procedural language. The code block is treated as though it were the body of a function with no parameters, returning void. It is parsed and executed a single time. The optional LANGUAGE clause can be written either before or after the code block.

Syntax

do ::= DO [ LANGUAGE lang_name ] code

do

DOLANGUAGElang_namecode

Semantics

code

The procedural language code to be executed. This must be specified as a string literal, just as in CREATE FUNCTION. Use of a dollar-quoted literal is recommended.

lang_name

The name of the procedural language the code is written in. If omitted, the default is plpgsql. The procedural language to be used must already have been installed into the current database. plpgsql is installed by default, but other languages are not.

Notes

If DO is executed in a transaction block, then the procedure code cannot execute transaction control statements. The attempt causes this runtime error:

2D000: invalid transaction termination

Transaction control statements are allowed with AUTOCOMMIT set to on—in which case the DO statement executes in its own transaction.

Examples

DO $$DECLARE r record;
BEGIN
    FOR r IN SELECT table_schema, table_name FROM information_schema.tables
             WHERE table_type = 'VIEW' AND table_schema = 'public'
    LOOP
        EXECUTE 'GRANT ALL ON ' || quote_ident(r.table_schema) || '.' || quote_ident(r.table_name) || ' TO webuser';
    END LOOP;
END$$;