What type will the comment field be?

The comment field type depends on the context and data requirements that will be recorded in it. Usually, string data types are used for comments, for example:

• In relational databases — TEXT or VARCHAR with sufficient length to hold arbitrary text.
• In systems supporting JSON — the field can be a string or even a JSON object if the comment contains structured data.

If comments can be very long, it is better to use a type with unlimited length, such as TEXT in MySQL or TEXT/CLOB in other DBMSs. If formatting support is important, the comment can be stored in Markdown or HTML format in a string field.