Focus on the output parameters of Oracle stored procedures

Oracle stored procedures refer to a set of precompiled SQL statements that can be executed in the database. Using stored procedures can simplify the execution of repetitive tasks, improve the efficiency of SQL statement execution, and can be used to process large amounts of data, thereby improving database performance.

Stored procedures can accept parameters as input and parameters as output. Among them, the output parameter of the stored procedure can be one or more, and can return a single or multiple values. This article will focus on the output parameters of Oracle stored procedures.

1. Definition of output parameters

In Oracle stored procedures, the syntax for defining output parameters is as follows:

OUT parameter_name [IN | OUT | IN OUT] datatype [(size)];

Among them,

• OUT: The specified parameter is an output parameter.
• parameter_name: Specify the name of the parameter.
• IN: The specified parameter is an input parameter.
• OUT: The specified parameter is an output parameter.
• IN OUT: The specified parameter is both an input parameter and an output parameter.
• datatype: Specifies the data type of the parameter.
• size: Specify the size of the parameter.

2. Use of output parameters

In Oracle stored procedures, output parameters can be used to return a single value or multiple values. Here are some examples of using output parameters:

1. Return a single value

CREATE OR REPLACE PROCEDURE proc_name (input_param IN datatype, output_param OUT datatype)
AS
BEGIN
    SELECT column INTO output_param FROM table WHERE condition = input_param;
END;

In the above code, output_param is an output parameter used to Returns the value of column in the query result.

2. Return multiple values

CREATE OR REPLACE PROCEDURE proc_name (input_param IN datatype, output_param1 OUT datatype, output_param2 OUT datatype)
AS
BEGIN
    SELECT column1, column2 INTO output_param1, output_param2 FROM table WHERE condition = input_param;
END;

In the above code, output_param1 and output_param2 are output parameters, respectively To return the values ​​of column1 and column2 in the query results.

3. Example analysis

In order to better understand the output parameters, let’s analyze an example below. Suppose we have a table named employee, which contains the employee's name (name), joining date (hiredate), and salary (salary) and other information.

Now, we want to create a stored procedure to query the employee's joining time and salary based on the employee's name.

CREATE OR REPLACE PROCEDURE get_employee_info (v_name IN employee.name%TYPE, v_hiredate OUT employee.hiredate%TYPE, v_salary OUT employee.salary%TYPE)
AS
BEGIN
    SELECT hiredate, salary INTO v_hiredate, v_salary FROM employee WHERE name = v_name;
END;

In the above code, v_name is an input parameter used to specify the employee name to be queried; v_hiredate and v_salary are both output Parameters, respectively used to return the values ​​of hiredate and salary in the query results.

4. Summary

This article focuses on the definition and use of the output parameters of Oracle stored procedures. Output parameters can be used to return a single value or multiple values, which can greatly improve the efficiency and performance of data processing. In practical applications, it is necessary to select appropriate output parameters according to specific situations in order to better complete the data processing task.

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