Look up master data and concatenate into table field.

Question

Hi,
I have a database table which has many fields including category and period.I am extracting these values from an csv file which also has  fields category and period.
Periods are like 001,002,003 etc.but in the table I need it like 0012008,0022008,0032008.
We only have the period coming in from the file ; the associated year would be deduced from the Category. Every category is associated with a year.Therefore , we have to maintain a master data table for these categories where you have the year associated (for the time being take 2008) and the ABAP program needs to read the category from the file , look up to the master data , pick up its year and concatenate with the period that is already mentioned in the file.
How to I achieve this
Ankit

Answer 1

Eugene, Atlaj
Your answers were very useful.
Eugene as you said,
I read the link you mentioned and I can use code
like this
DATA: mat LIKE /BI0/PMATERIAL-MATERIAL.
SELECT SINGLE MATERIAL FROM /BI0/PMATERIAL INTO mat
WHERE EANUPC = COMM_STRUCTURE-EANUPC AND OBJVERS = 'A'.
IF SY-SUBRC = 0.
RESULT = mat.
RETURNCODE = 0.
ELSE.
RETURNCODE = 8.
ENDIF.
But for each record of comm structure the selection quer y will touch the Data base. As Atlaj said, can I fill the internal table in the start routine and look it up in the update rules. I think the performance willbe increased. Could you give me code sample or link?
Thanks in ADV
Joe