-- Regression tests for prepareable statements. We query the content -- of the pg_prepared_statements view as prepared statements are -- created and removed.
SELECT name, statement, parameter_types, result_types FROM pg_prepared_statements;
PREPARE q1 ASSELECT1AS a;
EXECUTE q1;
SELECT name, statement, parameter_types, result_types FROM pg_prepared_statements;
-- should fail
PREPARE q1 ASSELECT2;
-- should succeed
DEALLOCATE q1;
PREPARE q1 ASSELECT2;
EXECUTE q1;
SELECT name, statement, parameter_types, result_types FROM pg_prepared_statements;
DEALLOCATE PREPARE q2; -- the view should return the empty set again SELECT name, statement, parameter_types, result_types FROM pg_prepared_statements;
-- parameterized queries
PREPARE q2(text) AS SELECT datname, datistemplate, datallowconn FROM pg_database WHERE datname = $1;
EXECUTE q2('postgres');
PREPARE q3(text, int, float, boolean, smallint) AS SELECT * FROM tenk1 WHERE string4 = $1AND (four = $2OR
ten = $3::bigintORtrue = $4OR odd = $5::int) ORDERBY unique1;
-- invalid type
PREPARE q4(nonexistenttype) ASSELECT $1;
-- create table as execute
PREPARE q5(int, text) AS SELECT * FROM tenk1 WHERE unique1 = $1OR stringu1 = $2 ORDERBY unique1; CREATE TEMPORARY TABLE q5_prep_results AS EXECUTE q5(200, 'DTAAAA'); SELECT * FROM q5_prep_results; CREATE TEMPORARY TABLE q5_prep_nodata AS EXECUTE q5(200, 'DTAAAA') WITH NO DATA; SELECT * FROM q5_prep_nodata;
-- unknown or unspecified parameter types: should succeed
PREPARE q6 AS SELECT * FROM tenk1 WHERE unique1 = $1AND stringu1 = $2;
PREPARE q7(unknown) AS SELECT * FROM road WHERE thepath = $1;
-- DML statements
PREPARE q8 AS UPDATE tenk1 SET stringu1 = $2WHERE unique1 = $1;
SELECT name, statement, parameter_types, result_types FROM pg_prepared_statements ORDERBY name;
-- test DEALLOCATE ALL;
DEALLOCATE ALL; SELECT name, statement, parameter_types FROM pg_prepared_statements ORDERBY name;
Messung V0.5 in Prozent
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(vorverarbeitet am 2026-08-08)
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