6.3.3. PRIMARY KEY
Uniquely identifies each row in a table
A combination of a
NOT NULLandUNIQUE
6.3. SQL Constraints — Python
Does something automatically
Prevents from duplicating information
Prevents from loss of integrity
6.3.1. NOT NULL
Ensures that a column cannot have a
NULLvalue
6.3.2. UNIQUE
Ensures that all values in a column are different
6.3.4. FOREIGN KEY
Uniquely identifies a row/record in another table
6.3.5. CHECK
Ensures that all values in a column satisfies a specific condition
6.3.6. DEFAULT
Sets a default value for a column when no value is specified
6.3.7. INDEX
Used to create and retrieve data from the database very quickly
Analog to notebook calendar tabs
