Answer / sandeep

Differences Between Connected and Unconnected Lookup:
connected

o Receives input values directly from the pipeline.

o uses Dynamic or static cache

o Returns multiple values

o supports user defined default values.

Unconnected

o Recieves input values from the result of LKP
expression in another transformation
o Use static cache only.
o Returns only one value.
o Doesn’t supports user-defined default values.
NOTES
o Common use of unconnected LKP is to update slowly
changing dimension tables.
o Lookup components are
(a) Lookup table. B) Ports c) Properties d) condition.

Lookup tables: This can be a single table, or you can
join multiple tables in the same Database using a Lookup
query override.You can improve Lookup initialization time
by adding an index to the Lookup table.
Lookup ports: There are 3 ports in connected LKP
transformation (I/P,O/P,LKP) and 4 ports unconnected LKP
(I/P,O/P,LKP and return ports).
o if you’ve certain that a mapping doesn’t use a
Lookup ,port ,you delete it from the transformation. This
reduces the amount of memory.
Lookup Properties: you can configure properties such as SQL
override .for the Lookup,the Lookup table name ,and tracing
level for the transformation.
Lookup condition: you can enter the conditions ,you want
the server to use to determine whether input data qualifies
values in the Lookup or cache .
when you configure a LKP condition for the transformation,
you compare transformation input values with values in the
Lookup table or cache ,which represented by LKP ports .when
you run session ,the server queries the LKP table or cache
for all incoming values based on the condition.
NOTE
- If you configure a LKP to use static cache ,you
can following operators =,>,<,>=,<=,!=.
but if you use an dynamic cache only =can be used .

- when you don’t configure the LKP for caching ,the
server queries the LKP table for each input row .the result
will be same, regardless of using cache
However using a Lookup cache can increase session
performance, by Lookup table, when the source table is
large.
Performance tips:
- Add an index to the columns used in a Lookup
condition.
- Place conditions with an equality opertor (=) first.
- Cache small Lookup tables .
- Don’t use an ORDER BY clause in SQL override.
- Call unconnected Lookups with :LKP reference
qualifier.

Answer / swetha

Connected and unconnected

Answer / rekha

CONNECTED /UNCONNECTED
CACHE/UNCACHE

tell me the informatica architecture

1 Answers   Banca Sella, Wipro,

---

how can u load the data in time dimension?

3 Answers  

---

What is the main difference between a Joiner Transformation and Union Transformation?

5 Answers  

---

After dragging the ports of 3 sources sqlserver,oracle,informix to single source qualiofier can we map these ports directly to target and how?

2 Answers  

---

how do u get the first record from 50,000 records ?

10 Answers   TCS, UBS,

---

What is a command that used to run a batch?

4 Answers  

---

i have 2 session s1 execute s2 load first session fail what is the reason?

1 Answers   L&T,

---

i have thousand records in my source(flat file) i wanna load 990 records i don't want load first 5 records and last 5 records at informatica level?

3 Answers   Satyam,

---

Explain in detail scd type 2 through mapping.

0 Answers  

---

in what type of scenario bulk loading and normal loading we use?

2 Answers   Cognizant, Wipro,

---

which one is better performance wise joiner or look up

0 Answers   Informatica,

---

How does the server recognize the source and target databases. Elaborate on this.

1 Answers  

---