1. FOCUS to DB2
By: Meadow Heath

2. FOCUS to DB2 Define DB2 table to FOCUS
How FOCUS processes a DB2 request
FOCUS to DB2 Efficiencies

3. Define DB2 table to FOCUS
CAR Master File Description
CAR Access File Description

4. CAR MFD FILE=CAR ,SUFFIX=SQLDS ,$ SEGNAME=CAR ,SEGTYPE=S0 ,$
FIELD=COUNTRY ,COUNTRY ,A10 ,A10 ,MISSING=OFF,$
FIELD=CAR ,CARS ,A16 ,A16 ,MISSING=OFF,$
FIELD=MODEL ,MODEL ,A24 ,A24 ,MISSING=OFF,$
FIELD=BODYTYPE ,TYPE ,A12 ,A12 ,MISSING=OFF,$
FIELD=SEATS ,SEAT ,I3 ,I4 ,MISSING=OFF,$
FIELD=DEALER_COST ,DCOST ,D7 ,D8 ,MISSING=OFF,$
FIELD=RETAIL_COST ,RCOST ,D7 ,D8 ,MISSING=OFF,$
FIELD=SALES ,UNITS ,I6 ,I4 ,MISSING=OFF,$
FIELD=LENGTH ,LEN ,D5 ,D5 ,MISSING=OFF,$
FIELD=WIDTH ,WIDTH ,D5 ,D5 ,MISSING=OFF,$
FIELD=HEIGHT ,HEIGHT ,A2 ,A2 ,MISSING=OFF,$
FIELD=WHEELBASE ,BASE ,D6.1 ,D8 ,MISSING=OFF,$
FIELD=FUEL_CAP ,FUEL ,D6.1 ,D8 ,MISSING=OFF,$
FIELD=BHP ,POWER ,D6 ,D6 ,MISSING=OFF,$
FIELD=RPM ,RPM ,I5 ,I4 ,MISSING=OFF,$
ALIAS column should be the same name as the column name defined to the DB2 table
MISSING = OFF default value and should be used with NOT NULL columns in DB2
MISSING = ON displays the FOCUS NODATA value for missing data
ACTUAL format is converted from the SQL Datatype: CHAR(n)=An, VARCHAR(n)=An, SMALLINT=I4, INTEGER=I4, DECIMAL=P, REAL=F4, FLOAT=D8,DATE=DATE . . .

5. CAR ACCESS File SEGNAME= CAR ,TABLENAME= '”IBI".”CAR"'
,KEYS= 0 ,WRITE= YES ,$
SEGMENT associates the Master File with table it describes
WRITE=YES (default) specifies read and write access using MODIFY and MAINTAIN
WRITE=NO Read-only access using MODIFY and MAINTAIN
PRIMARY KEY must be defined (if there is one)
KYFLD and IXFLD would be included for multi-table structures -- used for dynamic JOINs.
ALLOCATION for the Access File is done in the FOCSQL library
DYNAM ALLOC FILE FOCSQL DA {node}.FOCSQL.DATA

6. FOCUS to DB2 Processing High level diagram of process FOCUS Request
DB2 Interface
Results

7. FOCUS Request Programmer submits a FOCEXEC: TABLE FILE CAR PRINT CAR
MODEL
DEALER_COST
RETAIL_COST
END

8. High Level Diagram of Process
DB2
Interface
(creates SQL)
FOCUS
(Processing)
db2 request
focexec
Programmer executes FOCEXEC
FOCUS parses request and passes to DB2 Interface

9. DB2 Interface DB2 Interface translates the FOCEXEC into SQL code:
TABLE FILE CAR
PRINT CAR
MODEL
DEALER_COST
RETAIL_COST
END
SQL:
SELECT T1.CAR,T1.MODEL,T1.DCOST,T1.RCOST
FROM CAR T1 FOR FETCH ONLY;

10. High Level Diagram of Process
db2 results
DB2
Interface
(creates SQL)
FOCUS
(Processing)
results
db2 request
focexec d a t s q l
Programmer executes FOCEXEC
FOCUS parses request and passes to DB2 Interface
RDBMS
DB2 Interface builds SQL & passes to RDBMS
RDBMS retrieves data from DB2 table(s)
RDBMS returns data to DB2 Interface
Table
Table
FOCUS completes any process not handled by DB2
Results returned to programmer

11. Results FOCEXEC: TABLE FILE CAR PRINT CAR MODEL DEALER_COST
RETAIL_COST
END
SQL:
SELECT T1.CAR,T1.MODEL,T1.DCOST,T2RCOST FROM CAR T1 FOR FETCH ONLY;
RESULTS:
CAR MODEL DEALER_COST RETAIL_COST
JAGUAR V12XKE AUTO , ,878
JAGUAR XJ12L AUTO , ,491
JENSEN INTERCEPTOR III , ,850
DATSUN B210 2 DOOR AUTO , ,139
MASERATI DORA 2 DOOR , ,500 .
PEUGEOT DOOR , ,610

12. FOCUS to DB2 Efficiencies
Sorting Data
Selection Criteria
Data Calculations
How to determine efficiency

13. Sorting Data
Sorting Defined field
Sorting on DB2 field

14. Sorting on Define field
FOCEXEC:
DEFINE FILE CAR
NEW_NAME/A3 =EDIT(MODEL,'999');
END
TABLE FILE CAR
PRINT CAR
BY NEW_NAME
SQL:
SELECT T1.CAR,T1.MODEL FROM CAR T1 FOR FETCH ONLY;
RESULTS:
NEW_NAME CAR
B DATSUN
COR TOYOTA
DOR MASERATI .
BMW
NOTICE: Sort statement is not passed to DB2; FOCUS will have to sort the data before sending results back to the programmer.

15. Sorting on DB2 field FOCEXEC: DEFINE FILE CAR
NEW_NAME/A3 =EDIT(MODEL,'999');
END
TABLE FILE CAR
PRINT NEW_NAME
CAR
BY MODEL NOPRINT
SQL:
SELECT T1.CAR,T1.MODEL FROM CAR T1 ORDER BY T1.MODEL FOR FETCH ONLY;
RESULTS:
NEW_NAME CAR
B DATSUN
COR TOYOTA
DOR MASERATI .
BMW
NOTICE: ORDER BY statement is added to the SQL passed to DB2. DB2 will sort the data before returning results to FOCUS.

16. Selection Criteria
Selecting from fields created with User-written subroutines
Selecting from fields created with Edit feature

17. Selecting from fields created with User-written subroutines
FOCEXEC:
DEFINE FILE CAR
NEW_NAME/A3 =SUBSTR(24,MODEL,1,3,3,NEW_NAME);
END
TABLE FILE CAR
PRINT CAR
BY NEW_NAME
WHERE NEW_NAME LT 'C'
SQL:
SELECT T1.CAR,T1.MODEL FROM CAR T1 FOR FETCH ONLY;
RESULTS:
NEW_NAME CAR
B DATSUN
NOTICE: No selection criteria is passed to DB2; therefore, DB2 will pass all the data back, and FOCUS will have to complete the request.

18. Selecting from fields created with Edit Feature
FOCEXEC:
DEFINE FILE CAR
NEW_NAME/A3 =EDIT(MODEL,'999');
END
TABLE FILE CAR
PRINT CAR
BY NEW_NAME
WHERE NEW_NAME LT 'C'
SQL:
SELECT T1.CAR,T1.MODEL FROM CAR T1 WHERE ((SUBSTR(T1.MODEL,1,3)) < ‘C’) FOR FETCH ONLY;
RESULTS:
NEW_NAME CAR
B DATSUN
NOTICE: WHERE NEW_NAME LT ‘C’ is translated by the DB2 Interface.

19. Data Calculations
Calculations in a Compute
Calculations in a Define

20. Calculations with Compute
FOCEXEC:
TABLE FILE CAR
SUM
COMPUTE NEW_AMT/D7 =RETAIL_COST - DEALER_COST;
BY CAR
END
SQL:
SELECT T1.CAR,SUM(T1.DCOST),SUM(T1.RCOST) FROM CAR T1 GROUP BY T1.CAR ORDER T1.CAR FOR FETCH ONLY;
RESULTS:
CAR NEW_AMT
ALFA ROMEO ,330
AUDI
BMW ,262
DATSUN
JAGUAR ,748
JENSEN ,910
MASERATI ,500
PEUGEOT
TOYOTA
TRIUMPH
NOTICE: NEW_AMT is not translated by the DB2 Interface; therefore, FOCUS does this calculation once all the data is retrieved from DB2.

21. Calculations in Define
FOCEXEC:
DEFINE FILE CAR
NEW_AMT/D7 =RETAIL_COST - DEALER_COST;
END
TABLE FILE CAR
SUM NEW_AMT
BY CAR
SQL:
SELECT T1.CAR, SUM((T1.RCOST - T1.DCOST)) FROM CAR T1
GROUP BY T1.CAR ORDER BY T1.CAR FOR FETCH ONLY;
RESULTS:
CAR NEW_AMT
ALFA ROMEO ,330
AUDI
BMW ,262 .
TRIUMPH
NOTICE: NEW_AMT is passed to DB2 to do the calculation.

22. How to determine efficiency
Test efficiency with FSTRACE4
FSTRACE4 shows the translation into SQL code
1) DYNAM ALLOC FILE FSTRACE4 *
(OR ALLOCATE TO A FILE)
2) Execute your FOCEXEC
3) Review FSTRACE4 to verify that the DB2 Translator converted your FOCEXEC into SQL code where possible

23. Summary
Define DB2 table to FOCUS in the Master File Description and Access File Description

24. Define the DB2 table to FOCUS
Master File Description (MASTER)
FILE=CAR ,SUFFIX=SQLDS ,$
SEGNAME=CAR ,SEGTYPE=S0 ,$
FIELD=COUNTRY ,COUNTRY ,A10 ,A10 ,MISSING=OFF,$
FIELD=CAR ,CARS ,A16 ,A16 ,MISSING=OFF,$
FIELD=MODEL ,MODEL ,A24 ,A24 ,MISSING=OFF,$ .
FIELD=RPM ,RPM ,I5 ,I4 ,MISSING=OFF,$
Access File Description (FOCSQL)
SEGNAME= CAR ,TABLENAME= '”IBI".”CAR"'
,KEYS= 0 ,WRITE= YES ,$

25. Summary
Define DB2 table to FOCUS in the Master File Description and Access File Description
The DB2 Translator translates the FOCEXEC into SQL code to be passed to the RDBMS

26. High Level Diagram of Process
db2 results
DB2
Interface
(creates SQL)
FOCUS
(Processing)
results
db2 request
focexec d a t s q l
Programmer executes FOCEXEC
FOCUS parses request and passes to DB2 Interface
RDBMS
DB2 Interface builds SQL & passes to RDBMS
RDBMS retrieves data from DB2 table(s)
RDBMS returns data to DB2 Interface
Table
Table
FOCUS completes any process not handled by DB2
Results returned to programmer

27. Summary
Define DB2 table to FOCUS in the Master File Description and Access File Description
The DB2 Translator translates the FOCEXEC into SQL code to be passed to the RDBMS
Write your FOCEXEC to be more efficient by making DB2 do most of the work

28. DB2 should do most of the work
DB2 Translator should be able to convert your data processing into SQL code when:
Sorting Data
Selection Criteria
Data Calculations
Test efficiency with FSTRACE4

29. Questions