Mysql stored procedure is a set of SQL statements in large database systems to complete specific functions. It is stored in the database. After the first compilation, it does not need to be compiled again when called again. The user specifies the stored procedure. name and give arguments to execute it.
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mysql stored procedure is:
1. What is a stored procedure
Stored procedure (Stored Procedure) is a set of SQL statements in large database systems that are used to complete specific functions. They are stored in the database. After being compiled for the first time, they do not need to be compiled again when called again. The user specifies the name of the stored procedure and gives parameters (if the stored procedure has parameters) to execute it. Stored procedures are an important object in the database, and any well-designed database application should use stored procedures.
2. Create a stored procedure
Format:
DELIMITER $$ CREATE PROCEDURE `ProcedureName`(paramName paramType) BEGIN END$$ DELIMITER ;
Red font explanation:
ProcedureName: The name of the stored procedure you want to create
paramName: parameter name
paramType: parameter type
Note:
(1) Whether the stored procedure requires parameters depends on the actual situation (the content of the brackets does not need to be filled in);
(2) MySQL supports stored procedures starting from 5.0;
(3) DELIMITER and DELIMITER; are delimiters. Their function is to let the compiler know that the contents inside them are stored procedures. If these two parts are not written, the compiler will treat this code as an ordinary SQL execution;
(4) Between BEGIN and END is the content of the stored procedure, and our SQL is written in the middle;
3. Advantages and disadvantages of stored procedures
(1) Fast execution. Since the stored procedure has been pre-compiled, the compilation part is skipped when used, so the execution speed will be faster;
(2) Reduce network traffic. When using a stored procedure, you only need to call the method of the stored procedure. Compared with the SQL statement, the method name of the stored procedure is shorter. The statement calling the stored procedure is transmitted over the network, which reduces network traffic;
(3) Complex Usability. Create once and use it as needed;
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