UNIQUE(background_color,foreground_color) The following statement creates the shapes table with a UNIQUE constraint defined for the background_color and foreground_color columns: CREATE TABLE shapes( Here is the error message: Error while executing SQL query on database 'chinook': UNIQUE constraint failed: contacts.emailĬode language: SQL (Structured Query Language) ( sql ) Defining a UNIQUE constraint for multiple columns example VALUES ( 'Johnny', 'Doe', language: SQL (Structured Query Language) ( sql ) If you attempt to insert a new contact with the same email, you will get an error message: INSERT INTO contacts(first_name,last_name,email) VALUES ( 'John', 'Doe', language: SQL (Structured Query Language) ( sql ) The following example inserts a new row into the contacts table: INSERT INTO contacts(first_name,last_name,email)
The following statement creates a new table named contacts with a UNIQUE constraint defined for the email column: CREATE TABLE contacts( Defining a UNIQUE constraint for one column example Let’s take some examples of using the UNIQUE constraint.
SQLITE ORDER BY IGNORECASE UPDATE
Once a UNIQUE constraint is defined, if you attempt to insert or update a value that already exists in the column, SQLite will issue an error and abort the operation.
SQLITE ORDER BY IGNORECASE HOW TO
The following illustrates how to define a UNIQUE constraint for multiple columns: CREATE TABLE table_name( Or at the table level: CREATE TABLE table_name( The following shows how to define a UNIQUE constraint for a column at the column level: CREATE TABLE table_name(Ĭode language: SQL (Structured Query Language) ( sql ) Only at the table level, you can define a UNIQUE constraint across multiple columns. You can define a UNIQUE constraint at the column or the table level. To define a UNIQUE constraint, you use the UNIQUE keyword followed by one or more columns. Introduction to SQLite UNIQUE constraintĪ UNIQUE constraint ensures all values in a column or a group of columns are distinct from one another or unique. Summary: in this tutorial, you will learn how to use the SQLite UNIQUE constraint to ensure all values in a column or a group of columns are unique.
0 kommentar(er)
