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diff --git a/docs/html/xbc6.html b/docs/html/xbc6.html deleted file mode 100755 index 094545f..0000000 --- a/docs/html/xbc6.html +++ /dev/null @@ -1,153 +0,0 @@ -<!DOCTYPE HTML PUBLIC> -<HTML> -<TITLE>Xbase DBMS Chapter 6</TITLE> -<BODY BGCOLOR=#FFFFFF> -<H1><p align="center">Index Overview</p></H1> -<p align="center">Chapter Updated 12/09/22</p><hr> - -The objective of this chapter is to provide information regarding -the basic concepts of index processing for the Xbase library.<br><br> - - -<h2>Overview</h2> - -The Xbase library is designed to support multiple index types simultaneously. -Dbase, Clipper and Foxbase each had their own index formats and ultimately the -goal is to provide support for all the legacy index file formats. - -<br><br> -The 4.0.x rewrite includes the NDX and MDX formats. Earlier versions of the -library included NTX and CDX formats which will be brought forward into the -library rewrite at some point in the future. - - -<h2>Tags</h2> - -Each index file contains one or more tags depending on the file type. Each tag is a sort order -and has characteristics: Sort order (ASC or DESC), unique or not unique and some formats support filtering. -Each open table (dbf file) has an "active tag" for database operations. - -<h2>Index processing design</h2> - -The library is construcuted to handle index files with multiple tags per file. Single tag files like the NDX indices -are treated as a multi tag file, but there is only one tag. This allows for maximum flexibility for future -additional index types. - - - -<h2>Index updates</h2> - -The library automatically updates all tags in all open index files. - - -<br><br> -<h2>Index File Types</h2> - -<table border=1> -<tr><th>File<br>Type</th><th>Source</th><th>Max Tags<br>Per File</th><th>Auto Opened</th><th>Sort Order</th><th>Unique Keys</th> - <th>Reclaimed Nodes</th><th>Filter Support</th><th>Status</th></tr> -<tr> - <td>NDX</td><td>dBase</td> - <td><center>1</center></td> - <td><center>Optional</center></td> - <td>ASC only</td> - <td><center>Y</center></td> - <td><center>N</center></td> - <td><center>N</center></td> - <td><center>Available in 4.0.1</center></td> -</tr> -<tr> - <td>MDX</td><td>dBase</td> - <td><center>47</center></td> - <td><center>Yes</center></td> - <td><center>ASC or DESC</center></td> - <td><center>Y</center></td> - <td><center>Y</center></td> - <td><center>Y</center></td> - <td><center>Available in 4.0.1</center></td> -</tr> -<tr> - <td>NTX</td> - <td>Clipper</td> - <td><center>1</center></td> - <td><center>Optional</center></td> - <td><center>?</center></td> - <td><center>?</center></td> - <td><center>?</center></td> - <td><center>?</center></td> - <td><center>Pending upgrades</center></td> -</tr> -<tr> - <td>CDX</td> - <td>Fox Pro</td> - <td><center>?</center></td> - <td><center>?</center></td> - <td><center>?</center></td> - <td><center>?</center></td> - <td><center>?</center></td> - <td><center>?</center></td> - <td><center>Pending upgrades</center></td> -<tr> -<tr> - <td>IDX</td><td>Fox Pro</td><td></td><td></td><td></td><td></td><td></td><td></td><td>Undeveloped</td> -<tr> - -</table> - -<br><br> -<h2>Index/Tag Methods</h2> -<table border=1> -<tr><th>Method</th><th>Description</th></tr> - -<tr> - <td>xbDbf::CheckTagIntegrity</td><td>Checks a tag for missing or duplicate entries. Available if XB_DEBUG_SUPPORT is on.</td> -</tr> -<tr> - <td>xbDbf::CreateTag</td><td>Create a new tag.</td> -</tr> -<tr> - <td>xbDbf::DeleteTag</td><td>Delete existing tag.</td> -</tr> -<tr> - <td>xbDbf::Find</td><td>Find key value for the active tag.</td> -</tr> -<tr> - <td>xbDbf::GetFirsKey</td><td>Retrieve the first key for the active tag.</td> -</tr> -<tr> - <td>xbDbf::GetLastKey</td><td>Retrieve the last key for the active tag.</td> -</tr> -<tr> - <td>xbDbf::GetNextKey</td><td>Retrieve the next key for the active tag.</td> -</tr> -<tr> - <td>xbDbf::GetPrevKey</td><td>Retrieve the previous key for the active tag.</td> -</tr> -<tr> - <td>xbDbf::GetCurTag</td><td>Retrieve the tag name key for the active tag.</td> -</tr> -<tr> - <td>xbDbf::OpenIndex</td><td>Open an index file. Only used for index files that aren't automatically opened.</td> -</tr> -<tr> - <td>xbDbf::Reindex</td><td>Rebuild a tag. Available if XB_DEBUG_SUPPORT is on.</td> -</tr> -<tr> - <td>xbDbf::SetCurTag</td><td>Set current tag.</td> -</tr> -</table> -<br><br> -<h2>Internal Data Storage</h2> - -<table border=1> -<tr><th>Type<th>Stored in DBF as</th><th>Stored in NDX as</th><th>Stored in MDX as</th></tr> -<tr><td>C</td><td>Character data</td><td>Character data</td><td>Character data</td></tr> -<tr><td>F</td><td>Text numbers</td><td>xbDouble</td><td>xbBcd</td></tr> -<tr><td>N</td><td>Text numbers</td><td>xbDouble</td><td>xbBcd</td></tr> -<tr><td>D</td><td>Text YYYYMMDD</td><td>xbDouble Julian</td><td>xbDouble Julian</td></tr> -</table> -<br><br> -<hr> -<p><img src="xbase.jpg"><br><hr> -</BODY> -</HTML> |