JSQL can be used for implementing personal minidatabase, as tool for dynamic compilation and execution of user requests. JSQL uses notation more popular for object-oriented programming then for relational database. Table rows are considered as object instances and the table - as class of these objects. Unlike SQL, JSQL is oriented on work with objects instead of SQL tuples. So the result of each query execution is a set of objects of one class.
Query always returns set of objects from one table.
Standard C types are used for atomic table columns. There are no NULL values, except null references. I am completely agree with C.J. Date critics of three-value logic and his proposal to use default values instead. Arrays can be used as record components. Special exists quantor is provided for locating element in arrays.