Horizontal Sorting in Data Stage

Horizontal Combining

Combining primary rows with Secondary rows based on key column values The stage that perform  Horizontal combining are

• Join
• Look – up
• Merge

These Stage differ with each other w. r. t

1. input requirements
2. Treatment of unmatched records
3. Memory usage

Description	join	lookup	Merge
Input Names		Primary /i/p Reference lookup   S1 - -> lookup
Types of joins	Inner leftouter,right outer, full outer	Inner, leftouter	Inner left outer
i/p,o/p,rejects	n-i/p2- i/p1-o/p   No reject	n-i/p2- i/p1-o/p   1-reject	n-i/p1-o/p   n-1-rejects
key column Name requirements	Key column Name should be SAME	In general- optional   It should be SAME in look up file set	Key column name should in SAME
inner join type	p.k column values should have matching with “ALL” secondary records   o/p:10	p/k column values should have matching with “all” secondary records.   o/p	p.k columns values should have matching with “Any” secondary records.   o/p:10,20,30
i/p requirements w.r.to sorting primary sorting   secondary sorting	mandatory   mandatory	optional   optional	mandatory   mandatory
i/p requirements w.r.t de- duplication (remaining duplicates) primary   secondary	no need to de- duplicate- ok   ok	ok   warnings	warnings(make sure that primary should be de- duplicate)   ok
treatment of un matched records a.  primary   b.  secondary	drop(inner)Target(left)b.Drop(inner)   target(right)	drop/target/reject   only drop	drop/target   drop/reject
memory usage	light	heavy	light

lookup

Cross  verification of primary records with Secondary records. It is a processing Stage which performs Horizontal combining In Data stage we have 4 types of look – ups

Normal lookup

Look up at memory, that is all the Secondary records are copied  to the memory and primary records are cross verified with Secondary records at memory. Sparse look up Look – up at Source , that is each primary record is send to the Source for cross verification. look up, failure condition :-

1. Continue  left outer joins
2. Drop inner join
3. fail
4. Reject

Join

4  types of joins can be performed  

  Inner Join  T1 n T2 = {10, 20} Matched records from primary and Secondary Tables . Left outer join T1 n (t1 u t2)  = {10, 20, 30} Matched records from primary and Secondary Tables and unmatched   records from primary. Right outer join  T2 n (t1 u t2)  = {10, 20, 40} Matched records from primary and Secondary Tables and unmatched  records from Secondary. Full outer Join  T1 u T2 = {10,20,30, 40} Matched and un matched records from primary and secondary table  

Job :- look up

  Primary 

Sequential file 1 

Load primary.txt  columns select   state  Sequential file  0  Load primary.txt columns select   state  

Look –up 

Drag key column value “State” from primary to ref   In ref, for State, Set key = case less (that is case sensitive can look -up)  

  Dslink

  Click on yellow link on the TOP  Constraints Set look up failure = Drop   (or) Continue  (or) Reject Needs are reject link Output

1. (a) job :- Normal look –u p :-

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Dept  (4 rows)    [Secondary records are copied to memory, and primary are cross verified with Secondary at memory so, 4 rows]   oracle  0 Load dept  Set look up Type = Normal oracle  1 Load EMP look  up Map key Column Value “Dept no”Drag and drop required columnsSelect continue Compile and RUN   (b )Job :- Sparse look up when we need to use Sparse ?   Sol:-

1. When memory is insufficient
2. When primary records are relative less than Secondary records

• In Sparse :- (conditions apply)

1. If ref is data base, then it Supports only 2 inputs .

  Dept  (14 rows)  [Each primary record is send to the Source that is dept for cross verification So 14 rows] oracle 0 Load dept 1^st look – up Type = Sparse   o/p   Job:- Sparse look up Sequential file If Ref file is Sequential file, then we have an Stage called “Look up file set”  extension is .lfs     Sequential file 0   :-  load ref file Sequential file 1 :- load primary file Look up  Map key column value “State”Drag and drop required columnsàSet look – up failure = continueCompile and RUN   Look up file set Look up keysKey = State Keep = false Target look up file set  = D: /shilpa/new sql look up.lfs Look up Range Range look up = No Options Allow Duplicates = false

• Compile and RUN

Look up file set 

1. It creates indexing on that particular key   (key column value)
2. In look – up file such same key column Name Should be there]

• Copy the look up first set path

1. Now Delete ref Sequential file in (a)

  Paste the lookup file set in the place of ref SEQ file is   (a) In the lookup file  set  à paste the file name here there is no need to map in the look up first   Output 

  job :- Database Sparse look up   In Data base , we can use lookup file set if we have 2 ref Data bases   Output Range look up:-

1. job :- Grade based on Salary 

Oracle enterprise 1 Load EMP table  convert Sal to integer in EMP table Oracle enterprise 1  Load Sal grade table  Convert Grade, lo Sal, HSal to integer in Sal grade table  

 Lookup

EMP. Sal >= Sal grade . Lo Sal And EMP. Sal <= Sal grade . H Sal  Drag and Drop required columnsclick on constraintsSelect Drop/Continue Data Set PropertiesàFileBrowse  for file Range look up .ds Compile and RUN For indepth understanding of DataStage click on

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