Variable-Length Records

1. Variable-length records arise in a database in several ways:
   • Storage of multiple items in a file.
   • Record types allowing variable field size
   • Record types allowing repeating fields
2. We'll look at several techniques, using one example with a variable-length record:

    aaaaaaaaaaaa¯type account-list = record
   
   		 		 bname : char(22);
   
   		 		 account-info : array   of
   
   		 		 		 		 record;
   
   		 		 		 		 		 account#: char(10);
   
   		 		 		 		 		 balance: real;
   
   		 		 		 		 end
   
   		 end
   
   

   Account-information is an array with an arbitrary number of elements.

• Byte string representation
• Fixed-length representation