📄 compressedblobfields.htm
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<title>Compressing BLOB Fields</title>
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<span style="font-family:Helvetica,Arial; font-size:12pt; color:#000000"><b>Compressing BLOB Fields
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<span style="font-family:Helvetica,Arial; font-size:10pt; color:#010100">Absolute Database is capable to compress data stored in the BLOB (Binary Large OBject) fields.
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This option can significantly reduce database file size when you need to store large texts, RTFs, bitmap images or other binary data in the database table.
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BLOB field values are compressed / decompressed on-the-fly.
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Everything you need to do is just to specify the BLOB compression settings for appropriate table fields.
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BLOB compression settings could be specified independently for each BLOB field:
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<table width="100%" border="0" cellpadding="0" cellspacing="0"><tr valign="top"><td width="14"></td><td width="14"><span style="font-family:Helvetica,Arial; font-size:10pt; color:#010100"></span></span><span style="font-family:Helvetica,Arial; font-size:10pt; color:#000000"><font face="Symbol" size="2" color="#000000">·</font></span></td><td><span style="font-family:Helvetica,Arial; font-size:10pt; color:#000000"><a href=tabsadvfielddef_blobcompressio.htm>BlobCompressionAlgorithm</a>
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</span></td></tr></table><table width="100%" border="0" cellpadding="0" cellspacing="0"><tr valign="top"><td width="14"></td><td width="14"><span style="font-family:Helvetica,Arial; font-size:10pt; color:#000000"><font face="Symbol" size="2" color="#000000">·</font></span></td><td><span style="font-family:Helvetica,Arial; font-size:10pt; color:#000000"><a href=tabsadvfielddef_blobcompressi2.htm>BlobCompressionMode</a><span style="font-family:Helvetica,Arial; font-size:10pt; color:#010100">
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</span></span></td></tr></table><table width="100%" border="0" cellpadding="0" cellspacing="0"><tr valign="top"><td width="14"></td><td width="14"><span style="font-family:Helvetica,Arial; font-size:10pt; color:#010100"></span></td><td></td></tr></table><span style="font-family:Helvetica,Arial; font-size:10pt; color:#010100"></span><span style="font-family:Helvetica,Arial; font-size:10pt; color:#000000"><span style="font-family:Helvetica,Arial; font-size:10pt; color:#010100">
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</span></span><span style="font-family:Helvetica,Arial; font-size:10pt; color:#000000"><span style="font-family:Helvetica,Arial; font-size:10pt; color:#010100"><b>Example</b></span></span><span style="font-family:Helvetica,Arial; font-size:10pt; color:#000000"><span style="font-family:Helvetica,Arial; font-size:10pt; color:#010100">:
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</span></span><span style="font-family:Courier New; font-size:8pt; color:#000000"> <b>with</b> ABSTable1 <b>do</b>
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<b>begin
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</b> <span style="font-family:Courier New; font-size:8pt; color:#000080"><i>{specifying advanced field definitions}</i></span></span><span style="font-family:Courier New; font-size:8pt; color:#000000">
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<b>with</b> AdvFieldDefs <b>do</b>
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<b>begin</b>
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Clear;
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Add(<span style="font-family:Courier New; font-size:8pt; color:#000080">'EmpNo'</span></span><span style="font-family:Courier New; font-size:8pt; color:#000000">,aftAutoInc,<span style="font-family:Courier New; font-size:8pt; color:#000080">0</span></span><span style="font-family:Courier New; font-size:8pt; color:#000000">,False);
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Add(<span style="font-family:Courier New; font-size:8pt; color:#000080">'Name'</span></span><span style="font-family:Courier New; font-size:8pt; color:#000000">,aftString, <span style="font-family:Courier New; font-size:8pt; color:#000080">100</span></span><span style="font-family:Courier New; font-size:8pt; color:#000000">, False);
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{<span style="font-family:Courier New; font-size:8pt; color:#000080"><i>ZLib compression algorithm with the fastest compression mode</i></span></span><span style="font-family:Courier New; font-size:8pt; color:#000000">}
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Add(<span style="font-family:Courier New; font-size:8pt; color:#000080">'Text'</span></span><span style="font-family:Courier New; font-size:8pt; color:#000000">,aftMemo, <span style="font-family:Courier New; font-size:8pt; color:#000080">0</span></span><span style="font-family:Courier New; font-size:8pt; color:#000000">, False, caZLIB, <span style="font-family:Courier New; font-size:8pt; color:#000080">1</span></span><span style="font-family:Courier New; font-size:8pt; color:#000000">);
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<b>end</b>;
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CreateTable;
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<b>end</b>;
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</span><span style="font-family:Helvetica,Arial; font-size:10pt; color:#000000">
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<span style="font-family:Helvetica,Arial; font-size:10pt; color:#010100"><b>Note:</b></span></span><span style="font-family:Helvetica,Arial; font-size:10pt; color:#000000"><span style="font-family:Helvetica,Arial; font-size:10pt; color:#010100"> To change Blob compression settings in existing table, perform </span></span><span style="font-family:Helvetica,Arial; font-size:10pt; color:#000000"><span style="font-family:Helvetica,Arial; font-size:10pt; color:#010100"><a href=restructuringtables.htm>Restructure table</a></span></span><span style="font-family:Helvetica,Arial; font-size:10pt; color:#000000"><span style="font-family:Helvetica,Arial; font-size:10pt; color:#010100"> operation.
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