sqlite unique
sqlite uniue
-------------------------
CREATE TABLE contacts(
contact_id INTEGER PRIMARY KEY,
first_name TEXT,
last_name TEXT,
email TEXT NOT NULL UNIQUE
);sqlite unique
sqlite uniue
-------------------------
CREATE TABLE contacts(
contact_id INTEGER PRIMARY KEY,
first_name TEXT,
last_name TEXT,
email TEXT NOT NULL UNIQUE
);unique constraint mssql
USE AdventureWorks2012;
GO
CREATE TABLE Production.TransactionHistoryArchive4
(
TransactionID int NOT NULL,
CONSTRAINT AK_TransactionID UNIQUE(TransactionID)
);
GOsql unique
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);Copyright © 2021 Codeinu
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