retriving values from multiple tables and place those ones into a dataset

hi Friends,

I am facing a problem, i don't know how explain the problem. but I am trying.

I am developing an application in which there are nearly 50 fields. Previously I used a single table to all these fields. Now my clients wants to add another 30 fileds to thes same application. So, now, i don't want to place all fields into single tabel. So, i divided them and placed in 8 tables each table with 10 columns with Common Primary Key.

Then, I inserted some records. So, Insertion completed Successfully without any problem.

After that, I want to retrive all those fields into single dataset, based upon some conditions.

Eg: there are 4 tables like t1,t2,t3,t4; All tables contains some 10 to 15 columns each

for all these fields id is primary key.

t1 columns are: id, applicant name, address,phonenum,emailid,etc.

t2 columns are: id, filename, filenum,logindate,property,executivename, etc.

t3 columns are:i ...