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SET BLOCKSIZE to nbytes
Message
De
22/05/1997 16:17:24
Dragan Nedeljkovich (En ligne)
Now officially retired
Zrenjanin, Serbia
 
 
À
19/05/1997 12:53:47
Anthony Griffith
Bwia International Airways
Port of Spain, Trinidade
Information générale
Forum:
Visual FoxPro
Catégorie:
Autre
Divers
Thread ID:
00032794
Message ID:
00033329
Vues:
43
/ I want to change the size of my Memo field to minimum. / I use the SET BLOCKSIZE to 0 command but apparently it is not working. / I set the blocksize and add characters to the memo field. But I must pack / memo after to reduce the size ot the / table to an acceptable size. Pack Memo might help even when there is no change in block size. Anyway, the memo fields whose length is made bigger every once in a while tend to clutter the .fpt file with unused blocks. When first stuffing some content into a memo file, sufficient blocks are allocated to keep the content. Now, if you add some more to it, the allocated blocks are probably not enough anymore, so it just allocates new blocks for the complete memo at the end of the .fpt file, leaving the first blocks unused. It doesn't reuse blocks. The only way to stop them cluttering your disk is to Pack Memo (which is implicitely done when you just Pack the table). Set Blocksize affects creating new tables, or converting old FP/DBase tables to new format. In your case, Pack Memo worked, and reduced the ..fpt's size; Set Blocksize did nothing. You might try setting different block sizes and then copying your tables into new ones (having memos packed, just to be fair in measuring), just to see which size fits you best. Anyway, the legal values for Set Blocksize are 64, 128, 256 etc; values from 1 to 32 mean kilobytes per block. Another matter: issuing Append Blank is ok, since it doesn't take new blocks, but issuing an Sql-insert and then filling up the memo fields may create a new block at the end of .fpt, if the replaced value is longer (in blocks) than the Insert-ed value. One more, the first block is shorter 4 bytes or so, which are occupied with the header (contains length).

back to same old

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