tayaarmy.blogg.se - Create enum row in sequel pro

But, there are still many things to cover that I have left out of this blog post. This dive into the ENUM data type has been nothing short of stellar for me with all I have discovered, learned, and shared here. Some use cases may not benefit from or justify an ENUM.

As with anything, just because it is there does not necessarily mean you have to use it.

You can add another new element to an existing ENUM column with the ALTER TABLE command but you cannot change an existing individual element value.

MySQL’s ENUM is not the same as other vendor’s versions so compatibility may be an issue if moving to another RDBMS.

(I learned this and other valuable information in the blog post, A Comprehensive Guide to Using MySQL ENUM You must use ALTER TABLE to change an established ENUM data type value which may be expensive in terms of locking and resources.ENUM data types use less internal storage than those of other character types.ENUM columns are sorted by their order of implementation established during table creation.ENUM column values are case sensitive for returned query results, identical to their state at the time of table creation.The ENUM element’s index has no relation or bearing on a table INDEX.ENUM values must be a quoted string literal.The same applies to ORDER BY DESC queries (not shown). ENUM‘s are sorted by their acceptable values in that order they were implemented during table creation. | fruit | enum ( 'Pear', 'Cherry', 'Orange', 'Banana', 'Pineapple', 'Grape', 'Kiwi', 'Apple', 'Fig' ) In similar fashion, we have another ‘fruit’ table but this one uses a VARCHAR data type to store the fruit name: | fruit | enum ( 'Pear', 'Cherry', 'Orange', 'Banana', 'Pineapple', 'Grape', 'Kiwi', 'Apple', 'Fig' ) | YES | | NULL | | | Field | Type | Null | Key | Default | Extra | I’ll leave you to refer to that resource for additional specific details if interested.įor this oversimplified example, we are only accepting book genre types from the 3 values listed as shown for the genre column in the book_club table definition. Exact storage size information is located in section 11.8 Data Type Storage Requirements. The official documentation from section 11.4.4 The ENUM Type, mentions that there are storage benefits from using ENUM‘s. When you need a string data type column to only store allowable values from a preferred list, this is one area where an ENUM is a strong candidate. In truth, any of the other MySQL string data types (e.g., VARCHAR and TEXT) could have been used for this example but herein lies a potential use case for the ENUM. (Note: This example would be stored better with a normalized schema but I am only interested in covering the ENUM data type so normalization practices are not covered in this blog post.)

Suppose I have this simple table representing books shared in a book club for 3 specific genres: ‘Western’, ‘Fantasy’, and ‘Military’. Xubuntu Linux 16.04.5 LTS (Xenial Xerus).It by no means depicts actual data belonging to or being used by any party or organization. Note: All data, names or naming found within the database presented in this post, are strictly used for practice, learning, instruction, and testing purposes. Photo by Glenn Carstens-Peters on Unsplash