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...
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。 在编程过程,原本是想把这几...
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...
Define a primary key in the SQL Server Database Engine by using SQL Server Management Studio or Transact-SQL.
Learn about primary and foreign key constraints, important objects used to enforce data integrity in database tables.
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...
创建检查约束SQL Server 解决方案1:使用外键: CREATE TABLE P(X INT); CREATE TABLE Q ( a INT NOT NULL, b INT,CONSTRAINT PK_a PRIMARY KEY (a)CONSTRAINT check_T FOREIGN KEY (B) REFERENCES REFERENCES Q(c)) 解决方案2:使用自定义项(不推荐): CREATE FUNCTION udfCheck_T( @column --add the ...
(255), CONSTRAINT pk_PersonsID PRIMARY KEY (Id_P,LastName) ) 在 表已存在的情况下为"Id_P"列创建PRIMARY KEY 约束 MySQL/SQL Server/Oracle/MS Access ALTER TABLE Persons ADD PRIMARY KEY (Id_P) 命名PRIMARY KEY 约束,以及为多个列定义 PRIMARY KEY 约束 MySQL SQL Server/Oracle/MS Access ALTER ...
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....
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,