Mysql supports stored procedures starting from version 5.0. MySQL version 5.0 did not support stored procedures before, which greatly reduced the application of MySQL. MySQL has supported stored procedures since version 5.0, which not only improves the processing speed of the database, but also improves the flexibility of database programming.
The operating environment of this tutorial: windows7 system, mysql8 version, Dell G3 computer.
MySQL version 5.0 begins to support stored procedures.
Stored Procedure is a database object that stores complex programs in the database so that they can be called by external programs.
Stored procedures are a set of SQL statements designed to complete specific functions. They are compiled, created and saved in the database. Users can call and execute by specifying the name of the stored procedure and giving parameters (when needed).
The concept of stored procedures is very simple, it is code encapsulation and reuse at the SQL language level of the database.
Using stored procedures can not only improve the efficiency of database access, but also improve the security of database use.
For the caller, the stored procedure encapsulates the SQL statement, and the caller does not need to consider the specific implementation process of the logical function. Just a simple call, it can be called from programming languages such as Java and C#.
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Writing stored procedures requires slightly higher requirements for developers, but this does not affect the common use of stored procedures, because storage The process has the following advantages:
1) Encapsulation
Usually multiple SQL statements are required to complete a logical function, and parameters are likely to be passed between each statement. Therefore, writing logical functions is relatively It is a little more complicated, and the stored procedure can contain these SQL statements into an independent unit, so that the outside world cannot see the complex SQL statements, and only needs a simple call to achieve the purpose. And database professionals can modify the stored procedure at any time without affecting the source code of the application that calls it.
2) Can enhance the function and flexibility of SQL statements
Stored procedures can be written using flow control statements, which have strong flexibility and can complete complex judgments and more complex operations.
3) Can reduce network traffic
Because the stored procedure is run on the server side and the execution speed is fast, when the stored procedure is called on the client computer, only the Call statements, thereby reducing network load.
4) High performance
When the stored procedure is successfully compiled, it is stored in the database server. The client can call it directly in the future, so that all SQL statements will be executed from the server, thus Improve performance. However, it should be noted that the more stored procedures, the better. Excessive use of stored procedures will actually affect system performance.
5) Improve the security of the database and the integrity of the data
One way to improve the security of stored procedures is to use them as intermediate components. The stored procedures can perform related operations on certain tables. , and then the stored procedure is provided as an interface to external programs. In this way, external programs cannot directly operate database tables and can only operate corresponding tables through stored procedures. Therefore, security can be improved to a certain extent.
6) Make data independent
The independence of data can achieve the effect of decoupling, that is to say, the program can call stored procedures to replace executing multiple SQL statements. In this case, the stored procedure isolates the data from the user. The advantage is that when the structure of the data table changes, there is no need to modify the program when calling the table. The database administrator only needs to rewrite the stored procedure.
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