在MSSQL视图中创建主键：技术指南（mssql视图中创建主键）

Learning how to create primary keys in MSSQL views is a must-have skill for any professional SQL programmer. Primary keys are used to uniquely identify rows in tables, and they guarantee that you can always access the data you need without having issues with duplicate rows. In this guide, we’ll go over the basics of creating primary keys in MSSQL views.

First off, it’s important to remember that MSSQL views are the same as regular tables, just in a different format. So when you are creating a primary key for a view, you need to use the “CREATE VIEW” command. After that, you can add in the primary key constraint just like you would for a table.

For example, let’s say we have a view called “myView” and we want to create a primary key on the “id” column. The code would look like this:

“`sql

CREATE VIEW myView

AS

SELECT id,items FROM products

WHERE quantity > 0

GO

ALTER VIEW myView

ADD CONSTRAINT PK_myView_id

PRIMARY KEY (id)

GO

This code creates the view and then adds the primary key constraint. Once the primary key is applied, you can be sure that all data being pulled from the view will have a unique and then searchable value. 

It's important to note that MSSQL views cannot be used for primary key enforcement in the same way as a physical table. This means if you are looking for the ability to enforce primary keys for data modifications, you'll need to use a regular physical table instead.

Finally, there are a few guidelines to keep in mind when creating primary keys in MSSQL views. Make sure that any columns used for the primary key are a part of the view's SELECT statement and have a UNIQUE or non-NULL value assigned to them. This way, you can ensure that the data being pulled from the view is always valid and not duplicated by other rows.

In conclusion, creating primary keys in MSSQL views is a great way to increase data integrity and ensure that you can always access the data you need without any issues. With the right techniques and a bit of practice, you can easily use MSSQL views to create primary keys in order to guarantee data integrity.