Use SQL Server Management StudioCreate a primary keyIn Object Explorer, right-click the table to which you want to add a unique constraint, and select Design. In Table Designer, select the row selector for the database column you want to define as the primary key. If you want to select...
Creating a primary key in an existing table requiresALTERpermission on the table. Use SQL Server Management Studio In Object Explorer, right-click the table to which you want to add a unique constraint, and selectDesign. InTable Designer, select the row selector for the database column you ...
1. 确认违反Primary Key约束的具体错误信息 当违反Primary Key约束时,SQL Server通常会返回一个错误消息,指明违反了哪个约束以及哪个值导致了冲突。错误消息可能类似于: text Msg 2627, Level 14, State 1, Line 1 Violation of PRIMARY KEY constraint 'PK_YourTableName'. Cannot insert duplicate key in object...
Learn about primary and foreign key constraints, important objects used to enforce data integrity in database tables.
1 Prepare Procedure 准备程序,先要运行一下,以生成创建SQL Server Constraint/Index的脚本。 有五个关键的存储过程要先运行CreateKeyIndex.sql ,DropKeyIndex.sql,ScriptCreateTableKeys.sql,ScriptDropTableKeys.sql,G enerateDefaultCollation.sql 。目的如它的名字所示,创建索引和约束。
constraint DEF_UniqueCI_VarData default 'Data' ); create unique clustered index IDX_UniqueCI_KeyValue on dbo.UniqueCI(KeyValue); create table dbo.NonUniqueCINoDups ( KeyValue int not null, ID int not null, Data char(986) null,
also permits fast access to data when the primary key is used in queries. If a primary key constraint is defined on more than one column, values can be duplicated within one column, but each combination of values from all the columns in the primary key constraint definition must be unique....
MySQL / SQL Server / Oracle / MS Access: CREATETABLEPersons ( ID intNOTNULL, LastName varchar(255)NOTNULL, FirstName varchar(255), Age int, CONSTRAINTPK_PersonPRIMARYKEY(ID,LastName) ); Note:In the example above there is only ONEPRIMARY KEY(PK_Person). However, the VALUE of the prim...
The SQL Server (Transact-SQL) PRIMARY KEY constraint is used to ensure that all values in a column of a table are UNIQUE and NOT NULL. A table can have only one PRIMARY KEY constraint, and a primary key can consist of single or multiple columns (fields). SQL Server PRIMARY KEY ...
While SQL Server only allows one PRIMARY KEY constraint assigned to a single table, that PRIMARY KEY can be defined for more than one column. In a multi-column scenario, individual columns can contain duplicate, non-unique values, but the PRIMARY KEY constraint ensures that every combination of...