Explore Oracle stored procedure syntax and the implementation of these stored procedures

Oracle is the world's famous relational database management system. As a powerful database system, Oracle provides stored procedures to manage and perform large database operations. In this article, we will explore Oracle stored procedure syntax and the implementation of these stored procedures.

Oracle stored procedure is a special stored program designed to solve a series of data processing problems. Oracle stored procedures are composed of statements and code blocks, can be executed multiple times, and have a certain degree of conditional restrictions and control structures. Oracle stored procedures mainly consist of three parts: "create", "execute" and "delete".

Create stored procedures:

In Oracle, there are the following three methods to create stored procedures:

Method 1:

When creating, you need to use CREATE The PROCEDURE statement specifies the name, parameters, and execution process code of the stored procedure; among them, parameters can be divided into three types: IN, OUT, and IN OUT.

CREATE OR REPLACE PROCEDURE procedure_name（

    in_parameter_name、IN parameter_type)
    out_parameter_name OUT parameter_type )

AS
BEGIN

（执行代码块）

END;

Method 2:

In Oracle Use visual tools to create stored procedures in SQL Developer. The creation process is as follows:

1. Open SQL Developer;

2. Select "Database" and create a data connection;

3 .Select "Create Stored Procedure" from the logical interface "Procedures";

4. Enter the name and necessary parameters;

5. Write the execution code in the code block.

Method 3:

Use visual tools to create stored procedures in PL/SQL Developer. The creation process is as follows:

1. Open PL/SQL Developer;

2. Select "File"-"New"-"Procedure";

3. Set the name and type of the stored procedure, execution permissions and other relevant information;

4. Inform the SQL Developer management tool Write the execution code in the code block.

Execute the stored procedure:

The execution process of Oracle stored procedure is very simple and can be carried out in the following two ways:

Method 1: Execute in Oracle SQL Developer.

The execution command is as follows:

BEGIN

procedure_name(parameters);

END;

Method 2: Use PL/SQL Developer or SQL* Plus.

The execution command is as follows:

EXEC procedure_name(parameters);

Delete the stored procedure:

You can use the DROP PROCEDURE command to delete the stored procedure. Command As follows:

DROP PROCEDURE procedure_name;

Commonly used syntax in stored procedures:

1. IF… THEN… ELSE… Statement:

IF condition1 THEN

action1;

ELSIF condition2 THEN

action2;

....
ELSE
actionn;
END IF;

2. CASE Statement:

CASE {expression}

WHEN value1 THEN statement(s) 
WHEN value2 THEN statement(s) 
... 
ELSE statement(s)

END CASE

3. LOOP statement:

LOOP statement(s)
END LOOP;

4. WHILE statement:

WHILE condition LOOP

statement(s);

END LOOP;

5. FOR Statement:

FOR counter_variable IN [REVERSE] lower_bound..upper_bound LOOP

statement(s);

END LOOP;

6. EXCEPTION statement:

EXCEPTION

WHEN {exception [OR exception]} THEN statement(s);

Note:

1. In the stored procedure, the stored procedure name, parameter type and parameter name must be defined, otherwise it will not be recognized when defining the stored procedure.

2.Oracle stored procedures do not support function overloading.

3.Oracle stored procedures do not support expressions as parameters.

Summary:

Oracle is an extremely powerful relational database management system that supports the creation of a variety of stored procedures and provides a series of rich syntax to help developers better Write stored procedures. Oracle's stored procedures are extremely powerful and can be widely used in large-scale database operations. However, you still need to pay attention to related issues during actual use in order to avoid potential errors and problems.

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