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...
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 want to define as the primary key. If you want to select multiple columns, hold...
A unique index, UNIQUE constraint, or PRIMARY KEY constraint cannot be created if duplicate key values exist in the data. A unique nonclustered index can contain included nonkey columns. For more information, see Create an index with included columns....
Creates an IPrimaryKeyConstraint object that is associated with the specified IRelationalIndex object. 命名空间: Microsoft.SqlServer.Management.SqlParser.MetadataProvider 程序集: Microsoft.SqlServer.Management.SqlParser(在 Microsoft.SqlServer.Management.SqlParser.dll 中) 语法 C# 复制 IPrimaryKeyConstraint ...
In SQL Server, the Primary Key constraint is a column (or a set of columns) that uniquely identifies each row in the table, this constraint enforces uniqueness and ensures that no column that is part of the Primary Key can hold a NULL value. Only one Primary Key can be created for eac...
add constraint pk_employeeid primary key (id) 4:外键约束 外键约束用在确保数据完整性和两个表之间的关系上 先看例子 create table orders ( id int identity not null primary key, customerid int not null foreign key references customer(id), ...
You can create a unique constraint in SQL Server by using SQL Server Management Studio or Transact-SQL to ensure no duplicate values are entered in specific columns that don't participate in a primary key. Creating a unique constraint automatically creates a corresponding unique index....
You can create a unique constraint in SQL Server by using SQL Server Management Studio or Transact-SQL to ensure no duplicate values are entered in specific columns that don't participate in a primary key. Creating a unique constraint automatically creates a corresponding unique index. ...
] referenced_table_name [ ( ref_column ) ] | CHECK ( logical_expression ) } ::= [ CONSTRAINT constraint_name ] { { PRIMARY KEY | UNIQUE } { NONCLUSTERED ( column_name [ ASC | DESC ] [ ,... n ]) | NONCLUSTERED HASH ( column_name [ ,... n ] ) WITH ( BUCKET_COUNT =...
You can create a unique constraint in SQL Server by using SQL Server Management Studio or Transact-SQL to ensure no duplicate values are entered in specific columns that don't participate in a primary key. Creating a unique constraint automatically creates a corresponding unique index....