Coloana sql unic
Exemple de cod
constrângere unică mssql
USE AdventureWorks2012;
GO
CREATE TABLE Production.TransactionHistoryArchive4
(
TransactionID int NOT NULL,
CONSTRAINT AK_TransactionID UNIQUE(TransactionID)
);
GO
sql unic
This constraint ensures all values in a column are unique.
Example 1 (MySQL): Adds a unique constraint to the id column when
creating a new users table.
CREATE TABLE users (
id int NOT NULL,
name varchar(255) NOT NULL,
UNIQUE (id)
);
Example 2 (MySQL): Alters an existing column to add a UNIQUE
constraint.
ALTER TABLE users
ADD UNIQUE (id);Pagini similare
Pagini similare cu exemple
În alte limbi
Această pagină este în alte limbi
empty row
Русский
..................................................................................................................
English
..................................................................................................................
Italiano
..................................................................................................................
Polski
..................................................................................................................
한국어
..................................................................................................................
हिन्दी
..................................................................................................................
Français
..................................................................................................................
Türk
..................................................................................................................
Česk
..................................................................................................................
Português
..................................................................................................................
ไทย
..................................................................................................................
中文
..................................................................................................................
Español
..................................................................................................................
Slovenský
..................................................................................................................
Балгарскі
..................................................................................................................
Íslensk
..................................................................................................................
Popular în această categorie
Pagini populare cu exemple din categorie
empty row