Dynamic SQL lets programs accept or generate SQL statements at
    run time, in contrast to precompiled statements that must be
    embedded in the program before it is compiled. Unlike embedded
    statements, such dynamically executed SQL statements are not part
    of any source code but are created while the program is running.
    Dynamic SQL is useful when you cannot predict the type of SQL
    statement your program needs to process.

    To handle dynamically executed SQL statements, programs use
    embedded PREPARE statements to assign a name to the SQL statement
    created at run time and to prepare it for execution. The EXECUTE,
    dynamic DECLARE CURSOR, and DESCRIBE statements refer to that
    assigned name. You cannot qualify prepared statement names.

    Because they are prepared with embedded PREPARE statements, you
    can refer to dynamic statement names from programs only, not from
    interactive SQL.