For Multiple Columns -- add unique constraint to multiple columnsALTERTABLECollegesADDUNIQUEUnique_College (college_id, college_code); Here, the SQL command adds theUNIQUEconstraint tocollege_idandcollege_codecolumns in the existingCollegestable. Also,Unique_Collegeis a name given to theUNIQUEconstrain...
To allow naming of a UNIQUE constraint, and for defining a UNIQUE constraint on multiple columns, use the following SQL syntax: MySQL / SQL Server / Oracle / MS Access: ALTERTABLEPersonsADDCONSTRAINTuc_PersonIDUNIQUE(P_Id,LastName) To DROP a UNIQUE Constraint To drop a UNIQUE constraint, us...
UNIQUE(ID) ); To name aUNIQUEconstraint, and to define aUNIQUEconstraint on multiple columns, use the following SQL syntax: MySQL / SQL Server / Oracle / MS Access: CREATETABLEPersons ( ID intNOTNULL, LastName varchar(255)NOTNULL,
@Cacheable使用两个或多个参数作为缓存的key 常见的如分页查询：使用单引号指定分割符，最终会拼接为一...
-- Return the name of unique constraint. SELECT name FROM sys.objects WHERE type = 'UQ' AND OBJECT_NAME(parent_object_id) = N' DocExc'; GO -- Delete the unique constraint. ALTER TABLE dbo.DocExc DROP CONSTRAINT UNQ_ColumnB_DocExc; GO ...
error occurs if you try to add a new row with a key value that matches an existing row. If you specify a prefix value for a column in a UNIQUE index, the column values must be unique within the prefix length. A UNIQUE index permits multiple NULL values for columns that can contain ...
违反了唯一性约束，所以导致插入不正确。ORACLE违反唯一约束条件解决方法 java代码报错：java.sql.BatchUpdateException: ORA-00001: 违反唯一约束条件 (TTT.table)at oracle.jdbc.driver.DatabaseError.throwBatchUpdateException(DatabaseError.java:629)at oracle.jdbc.driver.OraclePreparedStatement.executeBatch(...
报错:Update row with Key (id)=(xxxx) multiple times或者duplicate key value violates unique constraint 问题原因:违反唯一性约束,执行UPDATE、INSERT ON CONFLICT或INSERT操作时,主键存在重复数据。 解决方法: 若INSERT语法报错:可以改为INSERT INTO xx ON CONFLICT的语法,实现主键去重,详情请参见INSERT ON CONFLIC...
下列範例會建立具有非叢集主鍵條件約束的數據表,然後在數據表上建立叢集數據行存放區索引。 由於數據行存放區數據表上的任何插入或更新也會修改非叢集索引,因此違反主鍵條件約束的所有作業都會導致整個作業失敗。 SQL --Create a primary key constraint on a columnstore table.--Create a rowstore table with a non...
UniqueConstraint 类型公开以下成员。属性展开表 名称说明 Clustered 获取或设置指定约束是否为聚集约束的值。 Columns 获取约束列的列表。 ConstraintIdentifier 获取或设置约束名称。 (继承自 Constraint。) FileStreamOn 获取或设置文件流的可选规范。 FirstTokenIndex 获取或设置第一个标记索引。 (继承自 TSqlFragme...