Let's talk about the use of Oracle temporary tables and stored procedures

In Oracle database, temporary tables and stored procedures are relatively common technical means, which can help us process and manage data more efficiently. This article will focus on the use of temporary tables and stored procedures.

The concept and use of temporary tables

The so-called temporary table is a table that only exists in the current session. Temporary tables are very useful. They can be used to store the results of a temporary calculation, or as a medium for data sharing between two concurrent tasks. Of course, when using temporary tables, we also need to pay attention to the following points:

1. Temporary tables only exist in the current session. Once the session is closed, the temporary tables will also be destroyed, so please use them with caution.
2. The space used by the temporary table is in Oracle's own RAM, not on the hard disk, so its size needs to be controlled based on actual needs.
3. The statements for querying temporary tables are basically the same as those for ordinary tables, except that "global temporary" needs to be added before the table name to indicate that the table is a temporary table.

For example, when creating a temporary table, you can use the following statement:

CREATE GLOBAL TEMPORARY TABLE temp_table

(

id NUMBER (10),

name VARCHAR(100)

)

ON COMMIT DELETE ROWS;

Among them, "ON COMMIT DELETE ROWS" means that in the transaction Delete records on commit, which is how temporary tables are generally set up. Of course, "ON COMMIT PRESERVE ROWS" is also an optional option, which means that records are retained when the transaction is committed and continue to be used for queries.

When we need to insert data into the temporary table, we can use the ordinary insert statement:

INSERT INTO temp_table(id, name) VALUES(1, 'Tom');

Temporary tables have many practical application scenarios, such as storing temporary data, filtering data, processing large amounts of data, etc. Through its efficient and fast features, our work efficiency can be greatly improved.

The concept and use of stored procedures

Stored procedures are also a very common technical means. Its main function is to encapsulate some operations so that we can call them easily when using them. A stored procedure can be said to be a set of predefined SQL statements that can be called multiple times, which facilitates our management and operation of the database.

The main advantages of stored procedures are as follows:

1. Single point of control. Since the stored procedure is stored in transaction units, that is, when we call the stored procedure, it will automatically start an internal transaction. These transactions will be processed uniformly after the stored procedure is executed, so the atomicity of the transaction can be guaranteed, and Can avoid some data consistency problems.
2. Reduce network bandwidth consumption. Because the stored procedure runs on the database server, the code stored inside it has much less network transmission overhead than the client program.
3. Improve performance. Stored procedures can use some internal techniques, such as using parameterized queries, using indexes, etc., which can improve query efficiency. And because the stored procedure is stored inside the database, duplication of code can be avoided and efficiency improved.

When creating a stored procedure, we need to use Oracle's PL/SQL language. PL/SQL is a powerful programming language. Its syntax is similar to C language, Java and other programming languages, but it has more powerful SQL integration functions. The following is a simple stored procedure example:

CREATE OR REPLACE PROCEDURE get_user_info

(

user_name IN VARCHAR2,

user_age OUT NUMBER

)

IS

BEGIN

SELECT age INTO user_age FROM user_table WHERE name = user_name;

END;

Where, "IN" and "OUT" represent the input and output parameters of the stored procedure. By using these parameters, we can output some personalized information to the client program after the stored procedure is executed.

Conclusion

Temporary tables and stored procedures are very practical technical means in Oracle database and can realize many efficient and flexible data operations. I hope this article can bring you some help and inspiration.

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