![]() An identifier that starts with double number signs (#) denotes a global temporary object. An identifier that starts with a number sign denotes a temporary table or procedure. A regular identifier that starts with the at sign always denotes a local variable or parameter and cannot be used as the name of any other type of object. The underscore (_), at sign or number sign (#).Ĭertain symbols at the beginning of an identifier have special meaning in SQL Server. The Unicode definition of letters includes Latin characters from a through z, from A through Z, and also letter characters from other languages. The first character must be one of the following:Ī letter as defined by the Unicode Standard 3.2. The names of variables, functions, and stored procedures must comply with the following rules for Transact-SQL identifiers. For local temporary tables, the identifier can have a maximum of 116 characters. WHERE = 10 -Identifier is a reserved keyword.īoth regular and delimited identifiers must contain from 1 through 128 characters. IDENTITY(1,1) NOT NULL,ĬONSTRAINT PRIMARY KEY CLUSTEREDįROM -Identifier contains a space and uses a reserved keyword. For example: USE AdventureWorks2022 ĬREATE TABLE -Identifier contains a space and uses a reserved keyword. Identifiers that do not comply with all the rules for identifiers must be delimited in a Transact-SQL statement. WHERE = 153479919 -Delimiter is optional. For example: USE AdventureWorks2022 įROM. Identifiers that comply with the rules for the format of identifiers might not be delimited. USE AdventureWorks2022 Īre enclosed in double quotation marks (") or brackets (). Regular identifiers are not delimited when they are used in Transact-SQL statements. ![]() Classes of identifiersĬomply with the rules for the format of identifiers. The names of variables, or the parameters of functions and stored procedures must comply with the rules for Transact-SQL identifiers. For example, two tables with names that differ only in case can be created in a database that has case-sensitive collation, but cannot be created in a database that has case-insensitive collation. Identifiers of objects in a database, such as tables, views, and column names, are assigned the default collation of the database. Identifiers of instance-level objects, such as logins and database names, are assigned the default collation of the instance. The collation of an identifier depends on the level at which it is defined. The PRIMARY KEY constraint has no identifier. This table also has an unnamed constraint. (Ke圜ol INT PRIMARY KEY, Description nvarchar(80)) For example, the following statement creates a table with the identifier TableX, and two columns with the identifiers Ke圜ol and Description: CREATE TABLE TableX ![]() The identifier is then used to reference the object. Identifiers are required for most objects, but are optional for some objects such as constraints.Īn object identifier is created when the object is defined. Servers, databases, and database objects, such as tables, views, columns, indexes, triggers, procedures, constraints, and rules, can have identifiers. Everything in Microsoft SQL Server can have an identifier. The database object name is referred to as its identifier. Applies to: SQL Server Azure SQL Database Azure SQL Managed Instance Azure Synapse Analytics Analytics Platform System (PDW) SQL analytics endpoint in Microsoft Fabric Warehouse in Microsoft Fabric
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