從COLUMNS 結構描述資料列集,SQL Server 會擷取 TABLE_CATALOG、TABLE_SCHEMA、TABLE_NAME、COLUMN_NAME、COLUMN_GUID、ORDINAL_POSITION、COLUMN_FLAGS、IS_NULLABLE、DATA_TYPE、TYPE_GUID、CHARACTER_MAXIMUM_LENGTH、NUMERIC_PRECISION 和NUMERIC_SCALE 資料行。 COLUMN_NAME、DATA_TYPE 和ORDINAL_POSITION 必...
说明:如果使用者使用 DBCOLUMNDESC 的 wType 成员来定义列的数据类型,OLE DB Driver for SQL Server 使用 DBPROP_COL_FIXEDLENGTH 来确定数据类型映射。 有关详细信息,请参阅ITableDefinition 中的数据类型映射。 DBPROP_COL_NULLABLER/W:读取/写入
The problem isNEWIDnotISNULL. When defining a column withINTOthe column is defined as nullable if...
expressions can returnNULL;NEWIDis defined as nullable soISNULL(NEWID(),NEWID())is nullable too.
alter table dbo.mytable alter column mycolumn INT NOT NULL; 15 alter table dbo.mytable add primary key (mycolumn); 16 --*/ 17 /* 18 Error: 19 Cannot define PRIMARY KEY constraint on nullable column in table 'mytable'. 20 Could not create constraint or index. See previous errors. ...
Martin Cairney SQL Server MVP Friday, August 26, 2016 6:52 AM Hi John, 1] Try adding default(0) to column which you want to being NULL. like as Make the column nullable and dont specify default value. Adding a '' or 0 instead of letting it nullable is performance intensive operatio...
SERVER CONFIGURATION SERVER ROLE SERVICE SERVICE MASTER KEY SYMMETRIC KEY TABLE TABLE column_constraint TABLE column_definition TABLE computed_column_definition TABLE index_option TABLE table_constraint TRIGGER USER VIEW WORKLOAD GROUP XML SCHEMA COLLECTION Backup & restore CREATE Collations DROP Permissions ...
UNIQUE constraint columns can be nullable. In SQL Server, a nonclustered index is created by default, unless specified otherwise.Note SQL Server allows only one row to contain the value NULL for the complete unique key (single or multiple column index), while Oracle allows any number of rows...
SQL Server 版本 错误和事件(6000 到 6999) 相关内容 本文包含错误消息号(范围为 6,000 到 6,999 之间),以及其说明,这是 sys.messages 目录视图中错误消息的文本。 如果提供了错误编号,可以通过它找到详细信息。有关错误号的完整范围,请参阅数据库引擎事件和错误列表。可...
All the values that make up the foreign key are set to their default values if the corresponding row in the parent table is updated or deleted. For this constraint to execute, all foreign key columns must have default definitions. If a column is nullable, and there's no explicit default ...