Variable Sized Records

Most databases allocate disk space in fixed size blocks that each contain a fixed number of records. The space allocated to each record is the maximum size that that record definition allows.

For example, let's say you have a table that contains a 6 digit fixed length part number, and a variable length part description that could be up to 1000 characters long. Under the definition above, a 10,000 record database would require at least 10,060,000 bytes of disk space.

But let's look a little closer at the facts behind our table. Our maximum part description is 1000 bytes, but that's only because we have a few parts with really long winded descriptions; most of our part descriptions have an average length of about 100 characters. This is where Texis comes in; it only stores what you use, not what you might use. This means that our table would only require about 1 MB of disk space instead of 10 Mbytes.

But wait, it doesn't stop there! We have another hat trick. Because we store our records in this manner we also remove the limitation of having to specify the maximum length of a variable length field. In Texis any variable field can contain up to a Gigabyte. (Not that we recommend 1 Gig fields.)


Copyright © Thunderstone Software     Last updated: Jun 9 2017
Copyright © 2017 Thunderstone Software LLC. All rights reserved.