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Oracle in a Nutshell
book

Oracle in a Nutshell

by Rick Greenwald, David C. Kreines
December 2002
Intermediate to advanced content levelIntermediate to advanced
928 pages
85h 29m
English
O'Reilly Media, Inc.
Content preview from Oracle in a Nutshell

Positional iterators

A positional iterator is similar to a named iterator, with two significant differences:

  • You do not use a column_name in the declaration for a positional iterator. The columns retrieved by the SELECT statement place their values into the iterator columns in the same position.

  • You use the following syntax to retrieve a row from the positional iterator into a series of host variables.:

    #sql {
      FETCH :iterator_name INTO :host_expression [, :host_expression ...]
    };

For a positional iterator that implements the sqlj.runtime.Scrollable interface, the FETCH clause can take the following forms:

FETCH PREVIOUS | PRIOR
FETCH FIRST
FETCH LAST
FETCH ABSOLUTE:(row_number)
FETCH RELATIVE:(relative_number)

The end_fetch method for the positional iterator returns a Boolean indicating whether the last row has been fetched.

With Oracle9i, you can implicitly declare a positional iterator by simply making it a host variable to receive the results of a SELECT statement. You retrieve data from the iterator with a FETCH CURRENT call.

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Publisher Resources

ISBN: 0596003366Errata Page