DUG Session 4488Creating Custom Files

Jeff ButeraHampshire Collegejbutera@hampshire.edu

Monday, March 10, 20084:05PM Hoover

Outline

• Custom files: To have or not to have?• Best Practices• Creation, schema population• Indexing• Triggers• WARNING: Unidata perspective!

Survey time: Do you have any? Many?

To Have or Not?

• Custom files a necessity (?!)• Don't add data elements to Datatel files• Get away from USER fields• Don't misuse existing data fields• Create custom co-files of Datatel's• Create pure custom files as needed• Stored computed columns are GREAT!

What Does Hampshire Have?

• Custom co-files sample:– H08.PERSON– H08.STUDENTS– H08.STUDENT.TERMS

• Pure custom sample:– H08.CR.DIV.DATA– H08.PS.VEHICLES– H08.WORK.FILE

• We have 138+ custom files

Best Practices

• Have custom file naming convention– H08.filename

• Have custom prefix naming convention– Xxxx.fieldname (pure custom)– XHpre.fieldname (Datatel cofiles)

• Don't use PERSON, ADDRESS as examples!

• Consistency is key

Best Practices

• Example: STUDENTS– Field prefix: STU.– Computed Column prefix: XSTU.

• Custom cofile: H08.STUDENTS– Field prefix: XHSTU.

Best Practices – Custom Cofiles

:LIST DICT H08.PERSON

XHPER.DIR.PHONE 13 Dir Phone 8L SXHPER.DIR.POBOX 15 Dir Box 6L SXHPER.DIR.ROOM 17 Dir Room 8L SXHPER.DIR.TITLE 14 Dir Title 60L MXHPER.DIR.TYPE 11 Dir Type 14L SXHPER.DIR.YEAR 29 Dir Year 6L S

Best Practices – Pure Custom

:LIST DICT H08.CR.DIV.DATA

XCDD.CREATED.BY 51 Created? 10L SXCDD.DIV 65 Division 2L SXCDD.EVAL.DATE 7 D4/ Eval Date 10R SXCDD.FF.IDS 10 FF IDS 10L MXCDD.FF.TYPES 11 Type 8L MXCDD.FILE.DATE 33 D4/ File Date 10R S

Creation

• Files created in toolkit on FS• Choose application wisely (tree read)

– Freeze field placement– File type– File as blob– File on App Server

• File NOT created when saving out!• Created under 'data' in R18. Not good.• We move all custom files, alter VOC.

Creation

Creation - Schema

• Elements added on DEL• Add your key first – good practice• Avoid multipart keys in ETK• Detail to DEP for details• Internal size on DEL now important• Note 'Display Size' on DEP too• Can view on FIQ

Creation - Schema

Creation - Schema

Creation – Computed Columns

• Computed columns defined on DCC• Values calculated on the fly at runtime• Often needed, but sometimes slow

• Stored computed column on DSCC• Extended Link Attribute Entry DDLA• Update Stored Computed Column USCC• Don't have to use Datatel functionality

Creation – Stored Computed Column

• Create data element to store value• Write batch process to calculate and

store value.• Run batch process periodically

(once/day) on changed records.• If updating once/day or less won't work,

consider a database trigger.• Datatel doesn't support realtime (yet?)

Creation – Stored Computed Column

• Realtime with trigger is good!• Database triggers can be invoked

whenever a record is udpated or deleted• Easy to recalculate stored computed

column values anytime record is written• Totally outside ETK.• AE or MODIFY forces recalculation.

Creation – Indexing

• Vastly improve queries• Index data elements used often• Indicies defined on FIDX (toolkit)• Indicies built on UTBI/UTBA• Index anything you routinely query• How often do we reindex?

Creation – Indexing

Creation – Indexing

Performance with Indexing

• H08.CR.DIV.DATA pure custom file• Defined 20+ indicies on it• 45721 records in fileSELECT H08.CR.DIV.DATA WITH XCDD.STU.PROGREP.STATUS='V'

• Indexed: 50 milliseconds• Non-indexed: 1432 milliseconds

Triggers

• Piece of executed code• Triggered by certain events• Code is Unibasic subroutine/function• Triggers invoked when record is

•Updated (written)•Deleted

Triggers

• Create subroutine with 5 arguments:EXECSTAT (0,1,2)DICT.FLAG (‘’, ‘DICT’)FILE (‘STUDENTS’)ID (‘0023450’)RECORD

• Compile and GLOBALLY catalog• CREATE.TRIGGER FILENAME SUBNAME UPDATE

Triggers

• On ALL custom files, I use triggers forADD/CHG OPER, DATE, TIMEWhy not Envision?

• We use triggers on some Datatel files too!• We use WORKORDERS for Phys Plant and IT• PPWP (Web Params) only allows single Plant Type

and single email address for web work orders• No problem – worked around with a trigger

Triggers

SUBROUTINE H08.UT.H08.CR.EVENTS(X.EXEC,X.DICT,X.FILE,X.ID,X.REC)

X.EXEC=2

IF X.DICT=’’ THEN

X.REC<4>=UPCASE(@LOGNAME)

X.REC<5>=DATE()

X.REC<6>=TIME()

IF X.REC<1>=’’ THEN

X.REC<1>=X.REC<4>

X.REC<2>=X.REC<5>

X.REC<3>=X.REC<6>

END

END

RETURN

:BASIC CUSTOM.SOURCE H08.UT.H08.CR.EVENTS

:CATALOG CUSTOM.SOURCE H08.UT.H08.CR.EVENTS FORCE

:CREATE.TRIGGER H08.CR.EVENTS H08.UT.H08.CR.EVENTS UPDATE

Triggers

• Where can you find more info?• Unidata Documentation (thin):

Developing Unibasic ApplicationsChapter 4 – Maintaining Data in FilesDatabase triggers pp. 4-6

Summary

• Custom files are easy• Keep your custom data separate• Index things you query against often• Think about stored computed columns

for CPU-intensive computed columns• Be consistent naming files/fields

Summary

Jeff ButeraHampshire College

jbutera@hampshire.edu

http://jeff.hampshire.edu