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  1. #1
    Join Date
    Jul 2013

    Question 2 tier replacement for isam

    We have a product that is multiuser with isam database. Need to increase our number of users and the isam db does not support well. We have the full source code for the product but we don't want to rewrite to change the db. Is there a 2 tier db that can function like the isam.

    The Isam db does not work with queries. It works with you open a file (table), you position to a record, read that record, write that record, move next, move previous, move first, move last, etc.

    Is there a 2tier db engine that works with similar commands?

  2. #2
    Join Date
    Feb 2004
    In front of the computer
    What platform (OS and which ISAM engine) are you currently using? There are a number of good ISAM file handler packages for "mini" and "Mainframe" architectures, but none that I know of for microcomputers (Windows and Mac). In many cases you can apply a "wrapper" like DL2 to a relational database like DB2 to get better performance without requiring a rewrite.

    If you give us more insight into what you're looking for we can probably help, but ISAM by itself is too generic. That's kind of like referring to a database as "SQL" but not specifying which database engine.

    In theory, theory and practice are identical. In practice, theory and practice are unrelated.

  3. #3
    Join Date
    Jul 2013
    The software we use is a windows desktop application written in VB6. The isam file handler that is proprietary, so there isn't an existing commercial option.

    All the ISAM calls go through a win32 dll that we can replicate the calls, just need to find a DB engine that we can function with the way the current code is written.

    Need to replicate the following calls:

    opentable(tablename) - opens a connection to the specified table. with the isam, it opens the data files on the file system).

    movenext - moves the record cursor to the next record

    moveprevious - moves the record cursor to the previous record

    movefirst - moves the record cursor to the first record

    movelast - moves the cursor to the last record

    read - reads the record that the cursor is currently positioned to into memory

    write - writes the record that was last read back into the db

    There are more commands, but if we can find something that works with these commands, I don't expect the others will be an issue.


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