Stored procedures in Oracle database are predefined PL/SQL programs that can be executed multiple times without rewriting. Stored procedures can be used with Oracle database to achieve more efficient functions such as data management, access control, data transformation, etc.
In practical applications, we usually need to return a value in the stored procedure for further processing, such as checking the program execution results, obtaining the execution results, etc. Therefore, this article will introduce the return value related content in Oracle stored procedures, including how to define the return value, how to obtain the return value, etc.
1. Define the return value of the stored procedure
1. Use OUT parameters
Oracle stored procedures can return values through OUT parameters. OUT parameters are essentially a parameter type of a stored procedure that can be assigned a value in the stored procedure and returned to the caller at the end of the stored procedure. When defining a stored procedure, you can set the parameter type to OUT, as shown below:
CREATE OR REPLACE PROCEDURE procedure_name(p_param1 IN type1, p_param2 OUT type2) IS BEGIN -- 存储过程主体 END;
In the above code, p_param2 is an OUT parameter with type2.
2. Use function return value
Another way to define the return value of a stored procedure is to use a function. A function is called in a stored procedure and the function returns a value as the result of the stored procedure, as shown below:
CREATE OR REPLACE FUNCTION function_name(p_param1 IN type1) RETURN type2 IS -- 函数主体 BEGIN RETURN result; END; CREATE OR REPLACE PROCEDURE procedure_name(p_param1 IN type1, p_result OUT type2) IS BEGIN p_result = function_name(p_param1); END;
In the above code, the stored procedure calls a function function_name and stores the return value in the p_result variable middle.
2. Obtain the return value of the stored procedure
1. Use the OUT parameter
When calling the stored procedure, you can use an OUT parameter as the return value to obtain the stored procedure's return value. The execution result is as follows:
DECLARE v_result type2; -- 存储过程返回结果 BEGIN procedure_name(param1, v_result); DBMS_OUTPUT.PUT_LINE('result:' || v_result); END;
In the above code, the stored procedure procedure_name stores the execution result in the v_result variable, and prints the result through the output statement.
2. Use function return value
When calling a stored procedure, you can use a variable to store the return value of the function and use it as the execution result of the stored procedure, as shown below:
DECLARE v_result type2; -- 存储过程返回结果 BEGIN v_result = function_name(param1); DBMS_OUTPUT.PUT_LINE('result:' || v_result); END;
In the above code, the stored procedure function_name stores the execution result in the variable v_result, and prints the result through the output statement.
In short, stored procedures are a very practical database programming technology. In practical applications, we often need to obtain execution results from stored procedures for subsequent processing. This article introduces two methods of defining the return value of a stored procedure and how to obtain the results. Readers can choose the corresponding method according to their actual needs.
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