FOREIGN KEY SAME TABLE error - but foreign key doesn't exist 我试图添加引用同一张表的外键约束。 1 2 3 4 5 IFNOTEXISTS(SELECT*FROMsys.foreign_keysWHEREobject_id=OBJECT_ID(N'[dbo].[FK_Documents_Parent]')ANDparent_object_id=OBJECT_ID(N'[dbo].[Documents]')) BEGIN ALTERTABLE[dbo].[Docu...
SQL Server two foreign keys for same column in other tableSadly, Microsoft's recommendation is sti...
DELETE 语句与 REFERENCE 约束"main_id_cons"冲突。该冲突发生于数据库"Stock"，表"db o.test_sub", column 'main_id'。语句已终止。产生这类信息的原因是，你创建了默认的外键约束。默认的就是，为了保证数据的完整性，比如有父子关系的两表。你必须先删除掉子表的数据，让父表的数据，没有子表...
It is worth noting that foreign keys allow NULL, while the primary key does not. In addition, a foreign key does not always have to reference a primary key of another table. It can also reference a column that has theUNIQUEconstraint. ...
SQLRETURNSQLForeignKeys( SQLHSTMT StatementHandle, SQLCHAR * PKCatalogName, SQLSMALLINT NameLength1, SQLCHAR * PKSchemaName, SQLSMALLINT NameLength2, SQLCHAR * PKTableName, SQLSMALLINT NameLength3, SQLCHAR * FKCatalogName, SQLSMALLINT NameLength4, SQLCHAR * FKSchemaName, SQLSMALLINT NameLe...
How a Foreign Key causes a deadlock? During the data insert operation of the foreign keys, SQL Server performs some extra operations to validating the inserted data over the parent table. In certain scenarios, such as batch insert operations, this data validation operation can lead to deadlocks...
2. Each value in this column is unique. A table can not have more than one "PRIMARY KEY" column. 4.3 Foreign Key 外键 SELECT*FROMalbumsWHEREartist_id=3; A foreign key is a column that contains the primary key of another table in the database. We use foreign keys and primary keys to...
(written or unwritten) that should be utilized in order to increase the readability of the data model. These may be applied to just about anything inside the database, including tables, columns, primary and foreign keys, stored procedures, functions, views, etc. Having covered the rules for ...
1 At least one option must be specified and the same clause must not be specified more than one time. unique-constraint: CONSTRAINTconstraint-namePRIMARY KEYUNIQUE(, column-name,BUSINESS_TIMEWITHOUT OVERLAPS) referential-constraint: CONSTRAINTconstraint-nameFOREIGN KEY1(, column-namePERIODBUSINESS...
23515 The unique index cannot be created or unique constraint added because the table contains duplicate values of the specified key. -603 23520 The foreign key cannot be defined, because all of its values are not equal to a parent key of the parent table. -667 23522 The range of values ...