MySQL 8 Cookbook

Using JSON

As you have seen in the previous chapter, to store data in MySQL, you have to define the database and table structure (schema), which is a major limitation. To cope with that, from MySQL 5.7, MySQL supports the JavaScript Object Notation (JSON) datatype. Earlier there was no separate datatype and it was stored as a string. The new JSON datatype provides automatic validation of JSON documents and optimized storage format.

JSON documents are stored in binary format, which enables the following:

• Quick-read access to document elements
• No need for the value to be parsed from a text representation when the server reads the JSON again
• Looking up subobjects or nested values directly by key or array index without reading all values before ...