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Should you store enum in database?
Additionally, readability of enum values directly in a database is poor. The reader needs to know the order of values in the enum to understand what is the meaning of individual numbers. Summing up, because of potential bugs which default JPA enum mapping may cause, I recommend to avoid it.
What is the use of enum in MySQL?
The ENUM data type in MySQL is a string object. It allows us to limit the value chosen from a list of permitted values in the column specification at the time of table creation. It is short for enumeration, which means that each column may have one of the specified possible values.
Why is enum useful?
When you need a predefined list of values which do represent some kind of numeric or textual data, you should use an enum. If you use enums instead of integers (or String codes), you increase compile-time checking and avoid errors from passing in invalid constants, and you document which values are legal to use.
How do you declare an ENUM in SQL?
USE WorldofWarcraft; CREATE TABLE [users] ( ID INT NOT NULL IDENTITY(1,1) PRIMARY KEY, username varchar(255), password varchar(255), mail varchar (255), rank ENUM (‘Fresh meat’, ‘Intern’,’Janitor’,’Lieutenant’,’Supreme being’)DEFAULT ‘Fresh meat’, );
Why do you need enums in a database?
By keeping the enum in your database, and adding a foreign key on the table that contains an enum value you ensure that no code ever enters incorrect values for that column. This helps your data integrity and is the most obvious reason IMO you should have tables for enums.
Can you save enum to DB as a string?
But since you have implicit conversion in place, class declarations are the only ones to be aware of the helper types. You can save the enum to the db as a string, and I agree with dotctor that it is not the best idea, but if you need to, you need to make a few changes. Add this extension class to your project.
How to check the enum table in Java?
FROM reftable LEFT JOIN enumtable ON reftable.enum_ref_id = enumtable.enum_id WHERE enumtable.enum_id IS NULL; The other half of this solution is to write some test code that checks that the Java enum and the database enum table have the same contents.
Is it better to declare an enum as a foreign key?
I often end up with a database table representing the Enum. You can enforce database consistency by declaring a foreign key — although in some cases it might be better to not declare that as a foreign key constraint, which imposes a cost on every transaction.