Flat File Validation Using Informatica

Summary:

The intention of this case study is to give an idea about validation of a flat file source using information in file trailor. File will contain total record count in trailor and same will be verified with actual record count received in file before loading to target. If file is found to be valid, loading will be done else a record will be inserted in status table indicating that file to be processes is invalid.

1. Objective

The intention of this case study is to give an idea about validation of a flat file source using information in file trailor. File will contain total record count in trailor and same will be verified with actual record count received in file before loading to target. If file is found to be valid, loading will be done else a record will be inserted in status table indicating that file to be processes is invalid.

Other scenarios:

2. Source Definition:

Sample flat file source is a comma separated values file having employee records. In addition file is having a header (starting with H) and a trailor (starting with T). Header record contains file sequence number and trailor record contains total number of records in file (including header and trailor record).

In sample file total records in file are 14 (including header and trailor). File trailor is “T14”.

Data records are having columns empno, ename, job, mgr, hiredate, sal, comm, and deptno.

3. Target Definition

3.1 Target T_FILE_PROCESS_STATUS

First target is relational table (oracle) T_FILE_PROCESS_STATUS and has below structure.

This table will be used to load file information when the file is not valid. In case of a valid file nothing will be loaded in this table. Example data in this table for invalid & valid file will be as shown below.

Process_Date	Header_SeqNo	Trailor_count	File_Record_count	Is_File_Valid
01/12/2010	1500	12	14	N
02/12/2010	1500	14	14	Y

3.2 Target EMPLOYEE

Second target is EMPLOYEE table with below structure.

4. Mappings

4.1 Mapping to validate the source file: m_ValidateSourceFile

Below shown is a prototype of the mapping to check if total record count of file matches with record count specified in trailor. If there is a mismatch then a status record will be inserted in T_FILE_PROCESS_STATUS. For a valid record count in trailor, no record will be inserted in target table.

4.1.1 Transformations used

a) exp_Header_Trailor:

This expression is used after Source Qualifier to identify file header and file trailor. In this expression total number of records in file is also calculated.

In expression define following variable ports and output ports.

Eg;

Input column; empno

Please see the below expression used in different Variable ports:

Port Name	Expression
v_HeaderSeqNo	IIF (SUBSTR (Empno, 1, 1) ='H', SUBSTR (Empno, 2), NULL)
v_TrailorRecCnt	IIF SUBSTR (Empno, 1, 1) ='T', SUBSTR (Empno, 2), NULL)
v_FileRecCnt	v_FileRecCnt + 1
O_ProcessDate	SYSDATE

Variable to extract header sequence number is v_HeaderSeqNo, variable to extract trailor record count is v_TrailorRecCnt and variable to count total number of records in file is v_FileRecCnt.

b) AGG_HEADER_TRAILOR_ROWCOUNT

Aggregator is used to make a single row for header sequence number, trailor record count and file record count.

Port Name	Datatype	Precision	Scale	I	O	V	Expression	Group By
O_ HeaderSeqNo	string	10	0	Y	Y
O_TrailorRecCnt	string	10	0	Y	Y
O_File_Rec_Cnt	interger	10	0	Y	Y
O_Prosess_date	Date/time	29	0	Y	Y			Y
O_File_header	interger	10	0		Y		Max(O_ HeaderSeqNo)
O_file_trailor	interger	10	0		Y		Max (O_TrailorRecCnt )
O_File_rec_count	interger	10	0		Y		Max(O_File_Rec_Cnt)

Port o_ProcessDate is specified as Group By port.

C) exp_VALIDATE_ROCCOUNT

This expression is used to compare trailor record count with file record count.

Output port o_IsFileValid uses below expression to check if trailor record count matches with file record count. If there is a mismatch then o_IsFileValid flag is set to ‘N’.

Port Name	Expression
O_isFile_Valid	IIF (o_FileTrailor != o_FileRecCount,'N')

d) FIL_INVALID_FILE

This filter will pass the row only when o_IsValidFile flag is ‘N’ i.e. trailor record count does not match with file record count.

Filter condition is o_IsFileValid = 'N'.

4.2 Mapping to load source file: m_LoadFile

This is simple source to target mapping with a filter in place to skip file header and trailor.

4.2.1 Transformations used

FIL_HEADER_TRAILOR

Filter is used to skip file header and trailor. Only data records will be passed and loaded to target T_EMPLOYEE.

Filter condition used is SUBSTR (Empno, 1, 1)! = ‘H’ AND SUBSTR (Empno, 1, 1) != 'T'

5. Sessions

Session tasks will be created corresponding to each mapping. Session s_ValidateSourceFile is for mapping m_ValidateSourceFile.

Session s_LoadFile is for mapping m_LoadFile. As date in source file is in DD-MON-YY format, DateTime Format String is changed from default to DD-MON-YY. All other settings are default.

6.  Workflow (wf_LoadFile):

Simple workflow as shown below is created using a start task and two session tasks.

Condition to execute session wf_LoadFile is defined as below expression.

IIF ($s_ValidateSourceFile.TgtSuccessRows = 0,

$s_ValidateSourceFile.Status = succeeded,

$s_ValidateSourceFile.Status = failed)

With this condition is place, session s_LoadFile will execute only when no row is being inserted to target by session s_ValidateSourceFile. As per the mapping logic, m_ValidateSourceFile will insert the row in target only when file is failed for validation. So no row inserted in target means file is valid and should be loaded to EMPLOYEE table using m_LoadFile mapping.

Using sample flat file to execute this workflow will insert no row in T_FILE_PROCESS_STATUS. 12 rows will be inserted to EMPLOYEE table.