→ SQL – Constraints → Comece a aprender / Download de MP3 Flashcards

questão		resposta
Ensures that a column cannot have a NULL value começar a aprender		NOT NULL
Ensures that all values in a column are different começar a aprender		UNIQUE
A combination of a NOT NULL and UNIQUE. Uniquely identifies each row in a table começar a aprender		PRIMARY KEY [MySQL:] UserId auto_increment primary key
Uniquely identifies a row/record in another table começar a aprender		FOREIGN KEY
Ensures that all values in a column satisfies a specific condition começar a aprender		CHECK
Sets a default value for a column when no value is specified começar a aprender		DEFAULT
Used to create and retrieve data from the database very quickly começar a aprender		INDEX
It's like a declaration of default value that increments by 1 for each record. começar a aprender		auto_increment SQLite: autoincrement

SQL – Constraints