This is called Record Level Access control. See "Editing record access privileges" in FileMaker Help and check out this particular sub section: "Entering a formula for limiting access on a record-by-record basis" for a description of how to set this up.
oh that is very cool. i am a little confused here when it says:
Then use the following calculation when defining custom record access privileges:
Record_Created_By = Get(AccountName)
where would i put that formula exaclty?
Inside the "limited" access option for a given table.
From the edit privilege set dialog:
Select custom privileges from the Records drop down.
Click a table listed in the Custom Record Privileges dialog that opens.
Select "Limited..." from any one of the drop downs across the bottom of this dialog.
PS. when playing with manage | security, it may be a good idea to save a copy of your file before you change anything. Then, if you accidentally lock yourself out of the file, you have an unlocked copy you can revert to.