云数据库 GAUSSDB-DEALLOCATE:示例

时间：2024-11-02 18:49:49

云数据库 GAUSSDB

示例

  
   
     
     
       --查看现有预备语句。
gaussdb=# SELECT name, statement, parameter_types FROM pg_prepared_statements;
 name | statement | parameter_types 
------+-----------+-----------------
(0 rows)

--创建q1,q2,q3，q4四个预备语句。
gaussdb=# PREPARE q1 AS SELECT 1 AS a;
PREPARE
gaussdb=# PREPARE q2 AS SELECT 1 AS a;
PREPARE
gaussdb=# PREPARE q3 AS SELECT 1 AS a;
PREPARE
gaussdb=# PREPARE q4 AS SELECT 1 AS a;
PREPARE

--再次查看现有预备语句。
gaussdb=# SELECT name, statement, parameter_types FROM pg_prepared_statements;
 name |          statement           | parameter_types 
------+------------------------------+-----------------
 q1   | PREPARE q1 AS SELECT 1 AS a; | {}
 q4   | PREPARE q4 AS SELECT 1 AS a; | {}
 q3   | PREPARE q3 AS SELECT 1 AS a; | {}
 q2   | PREPARE q2 AS SELECT 1 AS a; | {}
(4 rows)

--删除q4预备语句并查看剩余预备语句。
gaussdb=# DEALLOCATE q4;
gaussdb=# SELECT name, statement, parameter_types FROM pg_prepared_statements;
 name |          statement           | parameter_types 
------+------------------------------+-----------------
 q1   | PREPARE q1 AS SELECT 1 AS a; | {}
 q3   | PREPARE q3 AS SELECT 1 AS a; | {}
 q2   | PREPARE q2 AS SELECT 1 AS a; | {}
(3 rows）

--删除所有预备语句并查看剩余预备语句。
gaussdb=# DEALLOCATE ALL;
DEALLOCATE ALL
gaussdb=# SELECT name, statement, parameter_types FROM pg_prepared_statements;
 name | statement | parameter_types 
------+-----------+-----------------
(0 rows)

      

    

  
 