Briefly describe the use of Oracle stored procedures and SQL statements

Oracle stored procedures are a set of predefined PL/SQL blocks stored in the database, which can be executed through Name calls. It is often used in development to improve database processing efficiency and security.

SQL statement is the abbreviation of Structured Query Language, which is a standard language for operating relational databases. In the Oracle database, SQL statements can be executed through command line input, SQL development tools, or applications.

Stored procedures and SQL statements are two important programming methods for Oracle database. Let's take a closer look at the usage, advantages and disadvantages of Oracle stored procedures and SQL statements.

1. Oracle stored procedures

1. The concept of stored procedures

Oracle stored procedures are a database programming method that was born to solve the problems of database processing efficiency and security. . It can contain various SQL statements, control structures, variables, constants and other elements, and can perform a series of database operations (such as data query, data update, etc.) through simple calls.

2. Usage and advantages of stored procedures

Oracle stored procedures are executed through Name calls. They are simple to use and have high execution efficiency, which can improve database processing efficiency and data security. In addition, stored procedures also have the following advantages:

(1) Flexibility: Stored procedures support gradual development, can be developed in sections according to different needs, and then combined with each other to form a complete stored procedure;

(2) Maintainability: The stored procedure can be reused, thereby improving the maintainability of the code;

(3) Reusability: Some applications are embedded in the stored procedure, making it Become a bridge between applications and databases and can be reused.

3. The components of the stored procedure

The components of the stored procedure include the following:

(1) Name: The stored procedure must have a unique Name and must end with "CREATE PROCEDURE Name" starts;

(2) Parameter list: The stored procedure can contain input parameters and output parameters, which are defined when creating the stored procedure;

(3) SQL statement: SQL statements embedded in stored procedures are usually used to perform database operations and can be defined inside the stored procedure or in an externally called program.

2. SQL Statement

1. The concept of SQL statement

SQL (Structured Query Language) is the abbreviation of Structured Query Language and is a professional relational database. operating language. It can be used to create, update, delete, query tables, records, etc. in the database.

2. Types of SQL statements

(1) DDL statement: used for data definition (creation, modification and deletion of objects in the database).

Common DDL statements include Create, Alter, Drop, etc.

(2) DML statement: used for data operations (adding, modifying and deleting data, etc.).

Common DML statements include Insert, Update, Delete, etc.

(3) DCL statement: used for data control language (permission, recycling and update, etc.).

Common DCL statements include Grant and Revoke.

3. SQL statement execution method

SQL statements can be executed directly through a general command line method (such as sqlplus), or graphically operated through a visual development tool (such as TOAD) .

Compared with stored procedures, writing SQL statements is relatively simple, and the efficiency of a single operation is relatively high. However, SQL statements lack the modularity of stored procedures, which is not conducive to code reuse and maintenance.

In general, stored procedures are suitable for complex database operations with strong business logic. SQL statements are suitable for simple, single database operations. In actual development, stored procedures and SQL statements are often used in combination to complement each other and maximize the advantages of the two programming methods.

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