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Thread: DB size

  1. #1
    Join Date
    Mar 2004
    Location
    Slovenia
    Posts
    56

    Unanswered: DB size

    I am writing a report for college...And I can't figure it out sth...

    The problem is:

    I would like to estimate how big a database will be or it is...

    lets say that DB has only 1 table with 3 fields...without primary keys and indexes

    ref text 20
    num number long integer
    choice yes/no

    Now, the Microsoft documentation about Access 2000 says, that every charchter in text field takes two bytes (if not UNICODE compressed), Long integer takes 4 bytes and boolean takes 1 byte. If I sum all it takes 45bytes per record. Let say that I have 100 records...the TAble should be 4500bytes big.

    But this is not true if I check the file size. When I am changing sth in the record i offen get an 4096 bytes increase...This is exactly 2 times of the maximum length of the record.

    Could sb tell what is behind the DB growth when consideing appending new records?

    Thx in advance!

    Martin
    Back to the basics...

  2. #2
    Join Date
    Apr 2004
    Posts
    130
    I don't know the answer to your question, but a bit of experimenting should give you your answers. Out of curiousity, why is this important? If you are concerned with db size then you are running your desktop/server too close to the limit. I recommend to my customers that at least 1/3 of the desktop/server drive/drives should be empty. This usually leaves plenty of space for work files. Based on today's drive sizes of 20-30gb (desktop)minimum, and 18gb scsi (server) any Access db that reaches a size worth worrying about is too big for Access.
    Just my 2 cents
    Winston

  3. #3
    Join Date
    Mar 2004
    Location
    Nashville, TN
    Posts
    557
    Have you tried a compact and repair to see if the sizing u are using becomes more accurate.

    Also I think you havent added the db file itself into the equation.

    Hope this helps,
    JS
    Have you ever thought about thinking on purpose?

    Jarvis Stubblefield
    Patriot Designs
    Web/Database Development and Consulting
    The-Patriot.net by Patriot Designs

  4. #4
    Join Date
    Mar 2004
    Location
    Slovenia
    Posts
    56

    Only theory

    I have a DB (PriceList). It was 128MB big. After compacting and repairing was 78MB. I don't have no major problem with it anymore. But for my report I wanted to analyze how big the raw data is (without indexes, primary key, relations,...). So i started the calculation and I didn't get a proper result...

    I wanted to estimate how much bigger the database is when you apply replication on it. So I started to calculate fields in bytes and number of record and number of replications fields and number of records. And I was close to my result (71MB+indexes and additonal replications tables ). But then I made clean DB without replications (aditional fields and tables) and I got 19MB big DB and with applying indexes I got 25MB. And I was confused...(still am actually because this is much less then I calculated. raw data should be arround 40MB...

    Nevermind.

    Is there anybody who could tell how could I estimate the size of the DB if I got the stucture of a DB?
    Back to the basics...

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