another name for primary key

Reproduced: http://blog.csdn.net/sunrise918/article/details/5575054 In the past few days, I have thought about logical primary keys, business primary keys, and composite primary keys. I also searched for some discussions on the Internet. For more

Reprinted from: http://blog.csdn.net/sunrise918/article/details/5575054These days on the logical primary key, business primary key and composite primary key have some thinking, also searched the related discussion on the net, related discussion can

Primary Key and foreign key in the database, primary key of the database 1. What are primary keys and Foreign keys: A record in a relational database has several attributes. If one of the attribute groups (note that it is a group) uniquely

First, what is the primary key, foreign key:There are several attributes in a record in a relational database, which can be a primary key if one of the attribute groups (note is a group) uniquely identifies a record:Student Table (School number,

This article is referenced from:http://blog.csdn.net/bingqingsuimeng/article/details/51595560First, what is the primary key, foreign key:There are several attributes in a record in a relational database, which can be a primary key if one of the

First, what is primary key, foreign key:A record in a relational database has several properties, and if one of the attribute groups (note the group) uniquely identifies a record, the attribute group can be a primary key such as: Student form

In our database design, the primary key of the database table is unavoidable. Many may not think deeply about it. The design of the primary key has a great impact on the design of the entire database, therefore, we have to pay attention to it.

1. Definition 1.1 What are primary keys and foreign keys 1.2 The role of primary and foreign keys 1.3 Differences between primary key, foreign key, and index 2. Primary key (primary key) 2.1 Setting the primary key via

Hibernate primary key generation policy and hibernate primary key policy Hibernate Primary Key Generation Policy 1. Automatic growth of identity Applicable to MySQL, DB2, and ms SQL Server. It uses the primary key generated by the database to

The role of the primary and foreign keys of sql:Foreign key value rule: A null value or a reference primary key value.(1) When a non-null value is inserted, it cannot be inserted if the value is not in the primary key table.(2) When updating, you