topic Re: Mapping extract column names and values in Talend Studio

Mapping extract column names and values

Anonymous — Sat, 16 Nov 2024 06:51:29 GMT

Hi,

I have a database table that contains a number of columns that I ned to extract to a csv file. During the extract process I need to dynamically alter some of the column names and values based on a mapping table that I've built.

Example input (database)

col1 col2 col3

a	b	c
a	b	d
a	e	c

And after being mapped the output should look something like

ID Name col3

a	bar	c
a	bar	d
a	egg	c

I'm using Talent open studio so the dynamic schema components are not available to me . Any suggestions on how I can achieve this? I have done something similar previously however that data was pivoted so that the column names and values were obtained in the data and I could use a tmap to do the mapping

e.g

ID Attribute Value

a	col2	b
a	col3	d

Re: Mapping extract column names and values

vapukov — Tue, 15 Jan 2019 00:45:40 GMT

connect to tMap

- main table with main connection

- lookup table with lookup

use LEFT join by to columns:

- col1 == id

- col3 == value

map to output

- col1, col3 from main table

- attribute from lookup table

Re: Mapping extract column names and values

Anonymous — Tue, 15 Jan 2019 00:52:33 GMT

Hi @vapukov thanks for the quick reply. The problem is I need to map the column names dynamically as well, not just the values. My mapping table specifies old and new names for columns so col1 = ID etc. I don't think I can achieve that through a tmap

Re: Mapping extract column names and values

vapukov — Tue, 15 Jan 2019 01:01:36 GMT

yes, you can not ...

first of all -dynamic schema - do not help you as well

but, you could:

- redesign schema for more appropriate (if you can)

- use sql for achive what you need - both tables in database (even if it different databases - first step land data to the same database staging table), then use SQL for return mapped data (tSQLinput support any query, bot only table)

Re: Mapping extract column names and values

Anonymous — Tue, 15 Jan 2019 01:04:52 GMT

Thanks @vapukov Yes, I'm thinking I need to do this in the db and then Talend can handle the results. I guess I posted to see if there were any components to do this in Talend