• Status: Solved
  • Priority: Medium
  • Security: Public
  • Views: 637
  • Last Modified:

fetching records from Oracle

Hi,

I'm facing problem while fetching selected number of records from Oracle 8i.

e.g., We have huge number of records, say around 200,000 in oracle 8i. I had to fetch 20 records of the 200 records I need. These records are scattered through out the database.

When I write a query, say (select x,y,z from table_name where x_id="123" and rownum<=20), it is searching only the first 20 of the databse records and returning 2 records which matches with the above condition.  whereas, I'm expecting first 20 of the 200 records initially.

I have tried some of the jdbc API's  methods like one in Statement.  Statement.setMaxRows(int varCnt); Initial count in varCnt is 20 and I am increasing varCnt by 20 each time user hits next button.
  This will work but it takes hell lot of time. As it might be searching for 200,000 records first & then return only first 20 out of it which matches with above condition.

 Please let me know if some one face similar prob. and achive any success in geting next - prev functionality through jdbc.
0
joesat
Asked:
joesat
1 Solution
 
bobbit31Commented:
have you tried rs.setFetchSize(20)
0
 
CShantanuCommented:
Hi joesat,
   I had already submited your answer.But never mind here it is again.

   As per my understanding you are facing prob while fetching data from OracleDB as well as you want that data to be of specific volume,  say first 20 recs. then next 20 recs. If it is the case please try out this.

  1) You need to optimized ur query by creating index on the column you are searching for.
     create index on x_id with some name say inx_x_id;
  2) Build your query with query optimizer by adding following line after select. as follows

String query =    select /* + INDEX (table_name,inx_x_id) */ x,y,z from table_name where x_id ='123'

  3) that's it now your can create Statement Object.
     stmt   = connDB.createStatement();
     stmt.setMaxRows(valCnt);
     rs = stmt.executeQuery(query);
   
   Make sure for each hit of next button increase valCnt by some amount.

That's it.
All the best



 
0
 
bobbit31Commented:
CShantanu:

welcome to ee.  Please read the tips on comments and answers at the bottom of the page.  Usually, experts only post comments b/c when you propose an answer it locks the question from the view of the other experts.  
0
 
objectsCommented:
And it appears your 'proposed' solution is exactly what joesat is already doing.
0
 
joesatAuthor Commented:
thanks guys
0
Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

Join & Write a Comment

Featured Post

Free Tool: Subnet Calculator

The subnet calculator helps you design networks by taking an IP address and network mask and returning information such as network, broadcast address, and host range.

One of a set of tools we're offering as a way of saying thank you for being a part of the community.

Tackle projects and never again get stuck behind a technical roadblock.
Join Now