Learn to use Identifiers with Kuika.

What is an identifier?

Identifiers are syntax rules for names of tables, columns and such database objects. When used the identifier should identify the SQL implementation of the example or cover the variations used by different SQL implementations.

Unquoted identifiers

Unquoted identifiers can use letters (a-z), digits (0-9), and underscore (_), and must start with a letter.

If you are going to use an unquoted identifier, you are able to use letters (a-z), digits (0-9), and underscore (_) but you must start with a letter.

Depending on what SQL implementation you are using, other characters may be allowed. They can even be used as first letters.

  • MySQL: $ (source)

  • MS SQL: @, $, #, and other Unicode letters (source)

  • PostgreSQL: $, and other Unicode letters (source)

  • Oracle: $, #, and other letters from database character set (source)

  • Unquoted identifiers are case-insensitive.

How this situation is handled depends very much so on the SQL implementation you are using.

MySQL: Case-preserving, sensitivity depends on database setting and underlying file system.

MS SQL: Case-preserving, sensitivity defined by database character set, so can be case-sensitive.

PostgreSQL: Converted to lowercase, then handled like quoted identifier.

Oracle: Converted to uppercase, then handled like quoted identifier.

SQLite: Case-preserving; case insensitivity only for ASCII characters.

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