topic Re: TRUNCATE TABLE ONLY IF NECESSARY in Talend Studio

TRUNCATE TABLE ONLY IF NECESSARY

Anonymous — Tue, 18 Jun 2013 16:02:39 GMT

Hi,
i want read table and create different flow data filtering by a column.
For each flow i want truncate the target table of the flow only if the flow contain data.
It's possible to do?
See picture

Re: TRUNCATE TABLE ONLY IF NECESSARY

Anonymous — Tue, 18 Jun 2013 21:03:12 GMT

It is possible, but not in the way describe. You have to check before if your query would return datasets (replace the result columns with a count(*)) and depending on the result you have to truncate the tables in separate tOracleRow components.
Probably you already though this, sorry there is no easy way to solve this.

Re: TRUNCATE TABLE ONLY IF NECESSARY

alevy — Wed, 19 Jun 2013 06:53:10 GMT

The easiest way is include a row counter in each flow and put a tOracleRow between tMap and tOracleOutput. Make the statement something like: <row>.<column> == 1 ? "TRUNCATE TABLE <table>" : "SELECT Null"

Re: TRUNCATE TABLE ONLY IF NECESSARY

Anonymous — Wed, 19 Jun 2013 10:49:21 GMT

Hi,
how can I insert a row counter? I must use taggregaterow or something else? And after this:
<row>.<column> == 1 ? "TRUNCATE TABLE <table>" : "SELECT Null" --> I must truncate and insert if condition is true.
Whit your statement I can truncate but how can I insert?
Thanks in advance,
Gino.

Re: TRUNCATE TABLE ONLY IF NECESSARY

alevy — Wed, 19 Jun 2013 13:11:50 GMT

Use e.g. Numeric.sequence("out1",1,1) in tMap to create a row counter. Make sure the sequence has a different name for each flow to a different table.
tOracleRow just does the truncation for the first row that passes through. tOracleOutput still does the insert.