适用于:Databricks SQLDatabricks Runtime 将信息主键或信息外键添加为CREATE TABLE或CREATE MATERIALIZED VIEW语句的一部分。 若要将 check 约束添加到 Delta Lake 表,请在创建表后使用ALTER TABLE。 语法 使用table_constraint子句定义跨多个列的约束或将语法与列定义分开。
SQL Server 2022 (16.x) 引入了用于添加主键表约束和唯一键约束的可恢复操作。 有关启用和使用可恢复ALTER TABLE ADD CONSTRAINT操作的详细信息,请参阅可恢复添加表约束。 示例 有关示例,请参阅ALTER TABLE (Transact-SQL)。 后续步骤 ALTER TABLE (Transact-SQL) ...
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coordinate_cst.set_refstruct(ref:pose)# 设置ref pose 计算rmsd时使用;## 函数设置选其一# 1.设置bound function:coordinate_cst.bounded(True)# use harmonic (false) or bounded (true) constraintscoordinate_cst.cst_width(width:float)# width值coordinate_cst.cst_sd(sd:float)# sigma值# 2.设置harmonic...
SQL Server Azure SQL Database Azure SQL Managed Instance SQL database in Microsoft Fabric Specifies the properties of a PRIMARY KEY, FOREIGN KEY, UNIQUE, or CHECK constraint that is part of a new column definition added to a table by usingALTER TABLE. ...
In this article Syntax Arguments Remarks Examples See Also Applies to: SQL Server Azure SQL Database Azure SQL Managed Instance Specifies the properties of a PRIMARY KEY, FOREIGN KEY, UNIQUE, or CHECK constraint that is part of a new column definition added to a table by using ALTER ...
Convenciones de sintaxis de Transact-SQLSintaxissyntaxsql Copiar [ CONSTRAINT constraint_name ] { { PRIMARY KEY | UNIQUE } [ CLUSTERED | NONCLUSTERED ] (column [ ASC | DESC ] [ ,...n ] ) [ WITH FILLFACTOR = fillfactor [ WITH ( <index_option>[ , ...n ] ) ] [ ON { ...
What is the function of the constrain? The function of 'constrain' is to express the act of limiting, restricting, or inhibiting something in some way. 2 What is a constraint formula? In mathematics and physics, a constraint formula is an equation that outlines the limitations or restrictions...
The function DEREF for an example of dereferencing Restrictions on Rowid Constraints Rowid constraints are subject to the following restrictions: You cannot define a rowid constraint for the REF elements of a VARRAY column. You cannot subsequently drop a rowid constraint from a REF column. If ...
The function DEREF for an example of dereferencing Restrictions on Rowid Constraints Rowid constraints are subject to the following restrictions: You cannot define a rowid constraint for the REF elements of a VARRAY column. You cannot subsequently drop a rowid constraint from a REF column. If ...