Help Center/ GaussDB/ Developer Guide(Centralized_8.x)/ Stored Procedure/ Dynamic Statements/ Dynamically Calling Stored Procedures
Updated on 2024-06-03 GMT+08:00
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Dynamically Calling Stored Procedures

This section describes how to dynamically call store procedures. You must use anonymous statement blocks to package stored procedures or statement blocks and append IN and OUT behind the EXECUTE IMMEDIATE...USING statement to input and output parameters.

Syntax

Figure 1 shows the syntax diagram.

Figure 1 call_procedure::=

Figure 2 shows the syntax diagram for using_clause.

Figure 2 using_clause::=

The above syntax diagram is explained as follows:

  • CALL procedure_name: calls the stored procedure.
  • [:placeholder1,:placeholder2,...]: specifies the placeholder list of the stored procedure parameters. The numbers of the placeholders and parameters are the same.
  • USING [IN|OUT|IN OUT]bind_argument: specifies where the variable passed to the stored procedure parameter value is stored. The modifiers in front of bind_argument and of the corresponding parameter are the same.
  • Overloaded functions or stored procedures with placeholders cannot be called.
  • When a stored procedure is called, => cannot be used to skip parameters.
Example: 
-- Create the stored procedure proc_add.
gaussdb=# CREATE OR REPLACE PROCEDURE proc_add
(
    param1    in   INTEGER,
    param2    out  INTEGER,
    param3    in   INTEGER
)
AS
BEGIN
   param2:= param1 + param3;
END;
/
CREATE PROCEDURE
gaussdb=# DECLARE
    input1 INTEGER:=1;
    input2 INTEGER:=2;
    statement  VARCHAR2(200);
    param2     INTEGER;
BEGIN
   -- Declare the call statement.
    statement := 'call proc_add(:col_1, :col_2, :col_3)';
   -- Execute the statement.
    EXECUTE IMMEDIATE statement
        USING IN input1, OUT param2, IN input2;
    dbe_output.print_line('result is: '||to_char(param2));
END;
/
result is: 3
ANONYMOUS BLOCK EXECUTE
-- Delete the stored procedure.
gaussdb=# DROP PROCEDURE proc_add;
DROP PROCEDURE
Parent topic: Dynamic Statements