1. 1 What's Where: Using the Voyager Class Diagrams and Data Dictionary With Access Queries ELSUG October 9, 2008 Cathy Salika CARLI Consortium of Academic and Research Libraries in Illinois

2. Voyager is a relational database 2 A relational database is a bunch of tables. A table looks like a spreadsheet.

3. Voyager has about 400 tables 3 Some are things you probably expect PATRON, ITEM, CIRC_TRANSACTION Some are less obvious INV_LINE_ITEM_NOTES Some are used to look up common codes LOCATION, FINE_FEE_TYPE

4. The _ID Fields 4 Many tables have a sequentially assigned number in a column with “_ID” in its name.

5. The _ID Fields 5 Sometimes the relationship is made directly.

6. The _ID Fields 6 Sometimes there’s an intermediary.

7. Starting to Write a Query 7 First you have to figure out what data you need what tables the data are in how to correctly relate those tables This is easier if you know about Voyager because you use it regularly.

8. Starting to Write a Query 8 A good query is built a few tables at a time is tested at each step of the way has no extraneous tables

9. Starting to Write a Query 9 There are two tools to show you what’s in the tables and how the tables relate. Voyager Class Diagrams available on SupportWeb Voyager Data Dictionary in the Voyager Technical User’s Guide But I recommend that you use the CARLI version of these documents.

10. CARLI’s Class Diagrams 10

11. CARLI’s Data Dictionary 11

12. CARLI’s Data Dictionary Lists the columns in alphabetical order (except that the _ID fields come first) 12

13. CARLI’s Data Dictionary Serves as an index to the class diagrams 13

14. CARLI’s Data Dictionary Tells you which fields are in UNICODE so you can format them properly 14

15. CARLI’s Data Dictionary Includes comments on what’s in the fields 15

16. CARLI’s Data Dictionary Provides lots of tips about where to find things. 16

17. CARLI’s Data Dictionary Gives warnings about tables to avoid 17

18. CARLI’s Data Dictionary Provides help with tricky links 18

19. Where to Get Them 19 CARLI’s Data Dictionary and the additional Class Diagrams Are in SupportWeb, in the KnowledgeBase. Search for “CARLI” and you’ll find it. Will soon be in the EL Commons Are on these flash drives

20. Views 20 Both versions of the Data Dictionary include views. Their names end with _VW Inside Voyager, a view is actually a query, but you can use them as if they were tables. Some views are helpful, some are inefficient, some are WRONG. So let’s see which are which.

21. Good Views Call Nos. DEWEYCLASS_VW LCCLASS_VW NLMCLASS_VW SUDOCCLASS_VW UDCCLASS_VW 21 A call number is included in a view if the CALL_NO_TYPE in MFHD_MASTER says it should be there.

22. Good Views Fixed Field Data for Bibs MARCBOOK_VW MARCCOMPUTER_VW MARCMAP_VW MARCMUSIC_VW MARCSERIAL_VW MARCVISUAL_VW 22

23. Inefficient Views CIRCCHARGES_VW CIRCRENEW_VW FUNDLEDGER_VW ISSUES_VW ITEM_VW SERIALS_VW 23 Why I don’t like them Some use a dozen tables or more, so queries that use them are slow. You have to know too much to understand their quirks. (CIRCCHARGES_VW drops charge transactions if the item has been deleted.) It’s too hard to make your statistics consistent.

24. If you want to know what the views do and you have access to SQLPLUS on your server and you don’t mind reading a bit of SQL… here’s how. 24 SQL> set heading off SQL> set long 4500 SQL> column view_name fold_a newl SQL> column text newl newl newl newl SQL> select view_name, text from all_views where owner=‘XXXDB’ order by view_name;

25. Bad Views AUTHBLOB_VW BIBBLOB_VW MFHDBLOB_VW 25 They don’t work correctly for long records. When to use them: NEVER

26. And now, a commercial… 26 If you’re new to query writing in Voyager, consider attending 2 other sessions: “Scary Queries Laid to Rest” by Jean Vik at 8:30am “Idiomatic Access Reports” at 9:30am

27. Questions? Thank you! 27