Tomorrow's Presentation

Tomorrow night we will continue our series of presentations on functions.

This month I will give examples of sorting the data with in multiple fields by a single field. This example can't be done with a standard ORDER BY. In dealing with this we will cover using arrays, sorting arrays, array aggregates, returning more than one value from your function, using an expression's field names in your SELECT statement.

An example of how to reset all sequences in a schema, database, etc. We can roll back transactions but not sequences, so after testing a database the sequences will have gaps between what was last used and the current sequences. While this can be fixed one command at a time, it is nice to write a function to do this for us to clean up after testing a database before running the next set of tests. Because some people use MS Access as a front end into Postgres, I will go into some of the numeric size limitation between MS Access & Postgres. What happens when you reach the end of your sequence. How to find your sequences. How to find what is using your sequence. How to set what the next value of your sequence will be, etc.

There is so much to cover that the advanced functions will have to be spread out over several months.

Lloyd

Lloyd Albin
Database Administrator

Statistical Center for HIV/AIDS Research and Prevention (SCHARP)
Vaccine and Infectious Disease Division (VIDD)
Fred Hutchinson Cancer Research Center (FHCRC)
1100 Fairview Ave N., E3-129
P.O. Box 19024 * Seattle, WA 98109-1024
206.667.6477 * 206.667.4812 fax
Hours: 10:00am-6:00pm (Pacific)

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