什么是存储过程?

什么是“存储过程”，它们是如何工作的?

存储过程是由什么组成的(每个东西都必须是存储过程)?

当前回答

存储过程用于检索数据、修改数据和删除数据库表中的数据。你不需要每次在SQL数据库中插入、更新或删除数据时都写一个完整的SQL命令。

2013-12-19 05:25:56

其他回答

存储过程是一组预编译的SQL语句，用于执行特殊任务。

示例:如果我有一个Employee表

Employee ID  Name       Age  Mobile
---------------------------------------
001          Sidheswar  25   9938885469
002          Pritish    32   9178542436

首先，我正在检索Employee表:

Create Procedure Employee details
As
Begin
    Select * from Employee
End

在SQL Server上运行此过程:

Execute   Employee details

--- (Employee details is a user defined name, give a name as you want)

然后，我将值插入到Employee表中

Create Procedure employee_insert
    (@EmployeeID int, @Name Varchar(30), @Age int, @Mobile int)
As
Begin
    Insert Into Employee
    Values (@EmployeeID, @Name, @Age, @Mobile)
End

在SQL Server上运行参数化过程:

Execute employee_insert 003,’xyz’,27,1234567890

  --(Parameter size must be same as declared column size)

示例:@Name Varchar(30)

在Employee表中，Name列的大小必须是varchar(30)。

2013-06-13 10:16:48

存储过程主要用于在数据库上执行某些任务。例如

从数据上的一些业务逻辑获取数据库结果集。在一次调用中执行多个数据库操作。用于将数据从一个表迁移到另一个表。可用于其他编程语言，如Java。

2013-08-21 10:02:36

存储过程是一组已创建并存储在数据库中的SQL语句。存储过程将接受输入参数，以便多个使用不同输入数据的客户端可以通过网络使用单个过程。存储过程可以减少网络流量并提高性能。如果我们修改一个存储过程，所有的客户端都将得到更新后的存储过程。

创建存储过程的示例

CREATE PROCEDURE test_display
AS
    SELECT FirstName, LastName
    FROM tb_test;

EXEC test_display;

使用存储过程的优点

A stored procedure allows modular programming. You can create the procedure once, store it in the database, and call it any number of times in your program. A stored procedure allows faster execution. If the operation requires a large amount of SQL code that is performed repetitively, stored procedures can be faster. They are parsed and optimized when they are first executed, and a compiled version of the stored procedure remains in a memory cache for later use. This means the stored procedure does not need to be reparsed and reoptimized with each use, resulting in much faster execution times. A stored procedure can reduce network traffic. An operation requiring hundreds of lines of Transact-SQL code can be performed through a single statement that executes the code in a procedure, rather than by sending hundreds of lines of code over the network. Stored procedures provide better security to your data Users can be granted permission to execute a stored procedure even if they do not have permission to execute the procedure's statements directly. In SQL Server we have different types of stored procedures: System stored procedures User-defined stored procedures Extended stored Procedures System-stored procedures are stored in the master database and these start with a sp_ prefix. These procedures can be used to perform a variety of tasks to support SQL Server functions for external application calls in the system tables Example: sp_helptext [StoredProcedure_Name] User-defined stored procedures are usually stored in a user database and are typically designed to complete the tasks in the user database. While coding these procedures don’t use the sp_ prefix because if we use the sp_ prefix first, it will check the master database, and then it comes to user defined database. Extended stored procedures are the procedures that call functions from DLL files. Nowadays, extended stored procedures are deprecated for the reason it would be better to avoid using extended stored procedures.

2014-04-09 12:01:47

存储过程用于检索数据、修改数据和删除数据库表中的数据。你不需要每次在SQL数据库中插入、更新或删除数据时都写一个完整的SQL命令。

2013-12-19 05:25:56

存储过程是可以以多种方式执行的一批SQL语句。大多数主流DBMs都支持存储过程;然而，并非所有国家都这样做。您需要查看特定的DBMS帮助文档以了解细节。因为我最熟悉的SQL Server，我将使用它作为我的样本。

要创建一个存储过程，语法相当简单:

CREATE PROCEDURE <owner>.<procedure name>

     <Param> <datatype>

AS

     <Body>

例如:

CREATE PROCEDURE Users_GetUserInfo

    @login nvarchar(30)=null

AS

    SELECT * from [Users]
    WHERE ISNULL(@login,login)=login

存储过程的一个好处是，您可以将数据访问逻辑集中到一个地方，这样DBA就可以很容易地进行优化。存储过程还有安全方面的好处，可以将执行权限授予存储过程，但用户不需要对底层表具有读/写权限。这是反对SQL注入的良好的第一步。

存储过程也有缺点，主要是与基本CRUD操作相关的维护。假设对于每个表，您有一个插入、更新、删除和至少一个基于主键的选择，这意味着每个表将有4个过程。现在有一个400个表的数据库，其中有1600个过程!这还是在你没有副本的前提下你可能会有。

这就是使用ORM或其他方法自动生成基本CRUD操作的优点所在。

2009-01-19 22:57:15

什么是存储过程?

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