Unconnected Lookup Transformation in Informatica

• Passive Transformation

• Unlike Connected Transformation that receives input directly from the mapping pipeline, it receives input from the result of an expression in another transformation.

• Acts like a function. An actual parameter is passed to the unconnected lookup transformation. A formal parameter captures that value and returns a value.

Lookup Transformation

Create a mapping M_LKP_UNC.

Drag Source (EMP), Target(Dim_JOIN),

From the transformation Menu Create an Expression transformation T_EXP and a lookup transformation T_LKP_UNC.

Lookup Transformation

Project the required ports from SQ to T_EXP and add a new port DNAME in T_EXP. Uncheck the Input port. 

Edit the Lookup Transformation and add a new port IN_DEPTNO (Formal parameter). Set the datatype,size and precision same as that of DEPTNO.

Check the input port for IN_DEPTNO and return port for DNAME.

Go to Condition Tab and set the condition DEPTNO = IN_DEPTNO.

Lookup Transformation

In the Expression Transfromation T_EXP, build a formula in the Expression.

Go to Functions Tab, expand Lookup Folder. Double Click on Lookup Function :LKP.T_LKP_UNC().

Lookup Transformation

Go to PORTS tab and pass a parameter by dbl clicking DEPTNO.

:LKP.T_LKP_UNC(DEPTNO).

Lookup Transformation

Project the required ports from the EXP to the TGT.

Lookup Transformation

Define a workflow WKF_LKP_UNC.

Sepecify three connections: 

Source 

Target 

Lookup (Important) .Since it is an unconnected lookup it is compulsory to assign the Relational Source connection MEEN_SRC here ($Source does not work here). Give the lookup table name.

  

Lookup Transformation

Preview the Output.

Lookup Transformation