TVirtualTable IndexFieldNames

Discussion of open issues, suggestions and bugs regarding Virtual Data Access Components for Delphi, C++Builder, Lazarus (and FPC)
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Joined: Thu 14 Jan 2010 14:54

TVirtualTable IndexFieldNames

Post by segnew » Thu 14 Jan 2010 15:45

I need a fast method to locate data associated with components I create at runtime. I want everything as efficient as possible with a minimum of programming and am considering using a TVirtualTable.

As an example I have the following:
VT.IndexFieldNames := 'TableName';

What search method is used to locate the record?

How will performance be effected when I have a very large number of items in the table?

Also, I want to know how efficient the TVirtualTable is from a memory utilization standpoint. In some cases I just have a string(40) index and an integer. In others I have a string(40) index, an integer, and additional data that must be tracked.

How is memory allocated for new records?


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Post by Plash » Mon 18 Jan 2010 08:30

If you locate by a field from IndexFieldNames, VirtualTable uses optimal search method. Search can be fast even for a large number of records.

For each new record VirtualTable allocates a memory block which size is sum of fields sizes.

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