not understood what u said pootle. Any other data types which inserts date, time with mil secs. Because i had one table which did not had unique column. So how i can recognize individual column. for that i created one timestamp column. but at the same time more than 1 record is inserting. to avoid this problem i tried for inserting mil secs also. Ok can u tell me any alternative to recognize individual column. Like ROWNUM in oracle. Or any thing here like ROWID. I am new to Access. I am using Access 2003.
you cannot gurantee a timestamp column will be unique in a multi user environment. there is an infinitessimal rsik that two users may attempt to write a record at the same time. Id strongly reccomend you use an autonumbner column in place, or youwill have to set a unique index and trap for errors every time you try to write the value. there is a risk that someone could alter the value of the columns
Also, I suspect that you hope that if you insert 20 records in one query using NOW() for the datetime, and the TIMESTAMP uses milliseconds, then the 20 records will have different values. This is not the case - all 20 will be identical no matter what the precision of the column.
You can use a combination of your idea and Mark's - a timestamp and autonumber composite primary key\ unique index. The autonumber works as a "uniquifier" for your date column. This is assuming your queries will be of the sort "get me all records between x datetime and y datetime". If not, then the autonumber on its own would probably suffice as the PK.
hi healdem, pootle, all,
Ok i will try autonumber. But what i am doing actually. I created one table and inserting records from another table select query. At that time When the records from select query inserting to new table, is there any function or any thing to get autonumber into new table.