你可以通过使用 SQL Server Management Studio 或 Transact-SQL 在 SQL Server 中创建唯一约束,以便确保在未参与主键的特定列中不输入重复值。 创建唯一约束会自动创建相应的唯一索引。 备注 有关Azure Synapse Analytics 中的唯一约束的信息,请参阅Azure Synapse Analytics 中的主键、外键和唯一键。
SQL Server中的约束是一种用于限制表中数据的规则。它们可以应用于列级别或表级别,并确保数据库中的数据遵循特定的规则和完整性要求。以下是SQL Server中常见的约束类型和使用方法的详细解释: 主键约束(Primary Key Constraint):主键约束用于唯一标识表中的每一行数据。它要求列中的值是唯一且不为空的。一张表只能有...
適用於: SQL Server 2016 (13.x) 及更高版本 Azure SQL DatabaseAzure SQL 受控實例Microsoft Fabric 中的 SQL 資料庫 主索引鍵和外部索引鍵是兩種類型的條件約束,可用以強制執行 SQL Server 資料表中的資料完整性。 這些都是重要的資料庫物件。 主索引鍵條件約束 資料表中通常會有一個或多個資料行包含可...
《SQL Server 2012 Internals》有这么一段话: “ SQL Server maintains a set of tables that store information about all objects, data types, constraints,confguration options, and resources available to SQL Server. In SQL Server 2012, these tables are called the system base tables. Some of the sy...
master: master database stores all system level information for an instance of SQL Server. It includes instance-wide metadata such as logon accounts, endpoints, linked servers, and system configuration settings. model: model database is used as a template for all databases created on the instance...
注意:从SQL Server 2016 (13.x) 开始,此行为由 ALTER DATABASE 的 AUTOGROW_SINGLE_FILE 和 AUTOGROW_ALL_FILES 选项控制,跟踪标志 1117 不再有效。 有关详细信息,请参阅 ALTER DATABASE (Transact-SQL) 文件和文件组选项。范围:仅全局。 1118 强制在统一区而不是混合区分配页,以减少 SGAM 页的争用。 创...
database engine for Azure SQL Database is based on the same code base as the SQL Server database engine. Most importantly, the database engine in Azure SQL Database always has the newest SQL database engine bits. Version 12 of Azure SQL Database is newer than version 15 of SQL Server....
In this Article Database Management Drive business continuity SQL Server Security Handle privacy concerns Create database snapshots Concurrency control Queries and related Improve query performance Ways to query Add keys and indexes Perform transactions Using constraints and...
all other objects, including forms, reports, queries, macros, VBA modules, and linked tables to the back-end database. When you migrate an Access database, it's similar to a split database in that SQL Server is acting as a new back-end for the data that is now located...
Defines the table data type for a Transact-SQL function. The table declaration includes column definitions and column or table constraints. The table is always put in the primary filegroup. <clr_table_type_definition> ( { column_namedata_type } [ , ...n ] ) Applies to: SQL Server 2008...