I have a couple of scenarios:
Need to read the value of a column from three different tables in a predefined order and only 1 table will have the data
Read data from table1 if records are present for criteria given else read data from Table2 for given criteria
In Oracle Stored Procedures
The way these are being handled right now is to first get the count for a given query into a variable, and if the count > 0, then we execute the same query to read the actual data as in:
select count(*) from table1 into v_count if v_count > 0 then select data into v_data from table1 end if; Return v_data
This is being done to avoid the no_data_found exception, otherwise I would need three exception handler blocks to catch the no_data_found exception for each table access.
Currently I am reimplementing this with Cursors so that I have something like this:
cursor C1 is select data from table1; Open C1 Fetch C1 into v_data if C1%FOUND then Close C1 Return v_data End If
I wanted to find out which one is better from a performance point of view–the one with Cursors, or the one which does a Select into a variable and has three no_data_found Exception blocks. I don't want to use the two stage query process which we have currently.