Add support for JSON column with MySQL database

[michal-josef-spacek]

There were issue with MySQL issue.

I think that's about support of JSON column data type with MySQL database. This ticket is about the resolving of it.

[michal-josef-spacek]

Some things to do:

• JSON column support in column_info()
• Add tests for column_info() JSON
• Add JSON column data type support
• Add tests for JSON column data type

[michal-josef-spacek]

Ad JSON column support in column_info())

There is my #220

[michal-josef-spacek]

Ad Add tests for column_info() JSON)

I don't know how to deal with it. I think that's best to add column_info() test to each 40__DATATYPE__.t test file

[michal-josef-spacek]

Ad Add JSON column data type support)

MySQL has MYSQL_TYPE_JSON data type. Id of this data type is 245

The JSON datatype is internally stored as LONGBLOB or LONGTEXT.

My actual proposal for static const sql_type_info_t SQL_GET_TYPE_INFO_values[]= { is:

  { "json", SQL_WLONGVARCHAR, 16777215, "'", "'", NULL,
    1, 0, 3, 0, 0, 0, "json object", 0, 0, 0,
    SQL_WLONGVARCHAR, 0, 0, MYSQL_TYPE_JSON, 0
  },

[michal-josef-spacek]

Ad Add tests for JSON column data type)

I created #223 , which tests actual situation with no decoded output from MySQL. Test is working.