Package com.saxonica.functions.sql

Class SQLQueryFn

  • All Implemented Interfaces:
    Callable, Function, GroundedValue, Item, Sequence
    public class SQLQueryFn
extends SystemFunction
    This class implements the sql:query() extension function. Arguments:
    1. The connection
    2. The table name
    3. A sequence of column names
    4. (optional) A SQL predicate selecting the rows to be selected

    The result is a sequence of maps, one for each selected row: the maps hold one entry for each requested column, with the corresponding value from the table.

    • Constructor Detail

      • SQLQueryFn

        public SQLQueryFn()

    • Method Detail

      • call

        public Sequence call​(XPathContext context,
                     Sequence[] arguments)
              throws XPathException
        Description copied from interface: Callable
        Call the Callable.
        Parameters:
        context - the dynamic evaluation context
        arguments - the values of the arguments, supplied as Sequences.

        Generally it is advisable, if calling iterate() to process a supplied sequence, to call it only once; if the value is required more than once, it should first be converted to a GroundedValue by calling the utility method SequenceTool.toGroundedValue().

        If the expected value is a single item, the item should be obtained by calling Sequence.head(): it cannot be assumed that the item will be passed as an instance of Item or AtomicValue.

        It is the caller's responsibility to perform any type conversions required to convert arguments to the type expected by the callee. An exception is where this Callable is explicitly an argument-converting wrapper around the original Callable.

        Returns:
        the result of the evaluation, in the form of a Sequence. It is the responsibility of the callee to ensure that the type of result conforms to the expected result type.
        Throws:
        XPathException - if a dynamic error occurs during the evaluation of the expression