oracle stored procedure syntax

In Oracle database, a stored procedure is a set of predefined PL/SQL code blocks that can be stored and called in the database by name. They can contain business logic within themselves and allow database developers to reuse code and reduce the overhead of database access. The following is the syntax of Oracle stored procedures:

1. Creating stored procedures

Creating stored procedures requires the use of the CREATE PROCEDURE statement. The following is an example of creating a stored procedure:

CREATE PROCEDURE procedure_name
( parameter_name [IN | OUT | IN OUT] data_type [, ...] )
[IS | AS]
BEGIN
-- procedure body
END;

In this statement, procedure_name is the name of the stored procedure, and parameter_name is the parameter name and data type passed to the stored procedure. Parameters can be of IN, OUT or IN OUT type, representing input parameters, output parameters or input and output parameters respectively. The specific details are as follows:

• IN: Indicates input parameters and can only be referenced;
• OUT: Indicates output parameters, the initial value is NULL and must be assigned in the stored procedure;
• IN OUT: Indicates input and output parameters, which must be assigned initial values ​​in the stored procedure.

2. Stored procedure body

The stored procedure body is the main body of the stored procedure code. It is a block of code enclosed by the BEGIN and END keywords. The following is an example of a stored procedure body:

BEGIN
-- Perform some operations
SELECT * FROM my_table WHERE some_column = parameter_name;
-- More operations
END;

In this example, the stored procedure body first performs some operations, then selects the value with the column name parameter_name from the my_table table, and ends after performing more operations.

3. Stored procedure parameters

A stored procedure can accept zero or more parameters, so when creating a procedure, you need to define a parameter list for the stored procedure. The following is an example of a stored procedure parameter:

CREATE PROCEDURE my_proc
(val1 NUMBER, val2 VARCHAR2)
IS
BEGIN
-- Procedure body
END;

In this example, the stored procedure my_proc accepts two parameters val1 and val2. Their types are NUMBER and VARCHAR2 respectively.

4. Stored procedure return value

Stored procedures can have return values. In Oracle, the return value can be implemented using the OUT parameter. The following is an example of a stored procedure with a return value:

CREATE PROCEDURE my_proc
(val1 NUMBER, val2 NUMBER, result OUT NUMBER)
IS
BEGIN
result := val1 val2 ;
END;

In this example, the stored procedure my_proc accepts two input parameters val1 and val2 and returns their sum through the OUT parameter result.

5. Stored procedure calls

Stored procedures can be called in other PL/SQL blocks. The following is an example of calling a stored procedure:

DECLARE
result NUMBER;
BEGIN
my_proc(5, 10, result);
DBMS_OUTPUT.PUT_LINE('Result is: ' || result);
END;

In this example, the stored procedure my_proc accepts two parameters val1 and val2 and returns their sum using the OUT parameter result. When calling the stored procedure, pass the val1, val2 and result variables and output the result.

Conclusion

In the Oracle database, stored procedures are a powerful tool that play an important role in data processing and management. In addition to improving performance, it also improves data security, reliability and reusability. By mastering the syntax and usage of stored procedures, database administrators and developers can greatly improve work efficiency and database performance.

The above is the detailed content of oracle stored procedure syntax. For more information, please follow other related articles on the PHP Chinese website!