→ SQL – Constraints → Sāciet mācīties / Lejupielādēt MP3 flashcards

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

SQL – Constraints