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Tip of the Day
Dec 21, 2018

WEBINAR:

On-Demand

Building the Right Environment to Support AI, Machine Learning and Deep Learning


Using ENUM in MySQL Columns

ENUMs are very powerful definitions and they help attain data validation when the values are pre-defined. With this you can avoid application-level validation or the same can be extracted from the database and used in applications to define the validation data.

In the DDL below, we are defining a column named transport_type with its values defined in ENUM. This will ensure that the values are always validated by the database before any insertion or updation.

CREATE TABLE TransportTypes (
transport_type_id INT,
transport_type ENUM('Bus','Train','Flight')
);

The following is valid SQL:

-- -- -- -- -- -- -- -- -- -- -- --
INSERT INTO TransportTypes VALUES (1,'Bus'), (2,'Train'), (3,'Flight');

Below is an invalid SQL query. This results in error during the execution:
-- -- -- -- -- -- -- -- -- -- -- --
UPDATE TransportTypes set transport_type ='Train2' where transport_type_id=2;
Sridhar M S
 
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