Αποτελέσματα Αναζήτησης
If you're asking if a table can have multiple columns as a primary key, then for MS SQL Server, the answer is yes, and it's called a composite (corrected) key.
18 Αυγ 2019 · A composite primary key is a primary key consisting of multiple columns. Microsoft usually refers to these as multicolumn primary keys in its documentation. This article provides an example of creating a composite primary key using Transact-SQL in SQL Server.
25 Μαΐ 2021 · CREATE TABLE dbo.root ( root_id int NOT NULL, year int NOT NULL, field1 int NULL, field2 int NULL, fieldx int NULL ) ON [PRIMARY] ALTER TABLE dbo.root ADD CONSTRAINT PK_root PRIMARY KEY CLUSTERED ( root_id ) WITH( STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] CREATE TABLE dbo ...
A primary key is a column or a group of columns that uniquely identifies each row in a table. You create a primary key for a table by using the PRIMARY KEY constraint. If the primary key consists of only one column, you can define use PRIMARY KEY constraint as a column constraint: pk_column data_type PRIMARY KEY, ...
18 Απρ 2024 · In Table Designer, select the row selector for the database column you want to define as the primary key. If you want to select multiple columns, hold down the CTRL key while you select the row selectors for the other columns. Right-click the row selector for the column and select Set Primary Key.
22 Φεβ 2022 · Create Primary Key on Multiple Columns in SQL Server. In our examples, we created Primary Keys on single columns. If we want to create Primary keys on multiple columns, we need a different syntax. To add multiple columns as part of the Primary Key, we need to simply add comma-separated values of the column names that should be part of the ...
To allow naming of a PRIMARY KEY constraint, and for defining a PRIMARY KEY constraint on multiple columns, use the following SQL syntax: MySQL / SQL Server / Oracle / MS Access: CREATE TABLE Persons ( ID int NOT NULL, LastName varchar (255) NOT NULL, FirstName varchar (255), Age int, CONSTRAINT PK_Person PRIMARY KEY (ID,LastName) );
