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| author | Jörg Frings-Fürst <debian@jff-webhosting.net> | 2023-08-14 19:45:36 +0200 |
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| committer | Jörg Frings-Fürst <debian@jff-webhosting.net> | 2023-08-14 19:45:36 +0200 |
| commit | bfa452a375ea0a0a3f95304a69186936567e5263 (patch) | |
| tree | aade062a143c1afcc4ea06ee27905ffc34a9217b /docs/html/xbc3.html | |
| parent | dd70ff8bf32c2d7ed365004b1770058265db1978 (diff) | |
New upstream version 4.1.4
Diffstat (limited to 'docs/html/xbc3.html')
| -rwxr-xr-x | docs/html/xbc3.html | 73 |
1 files changed, 0 insertions, 73 deletions
diff --git a/docs/html/xbc3.html b/docs/html/xbc3.html deleted file mode 100755 index f2f4a1d..0000000 --- a/docs/html/xbc3.html +++ /dev/null @@ -1,73 +0,0 @@ -<!DOCTYPE HTML PUBLIC> -<HTML> -<TITLE>Xbase DBMS Chapter 3</TITLE> -<BODY BGCOLOR=#FFFFFF> -<H1><p align="center">Fields and Strings</p></H1> -<p align="center">Chapter Updated 11/21/22</p><hr> - -<br><br> -The main objective of this chapter is to provide basic information regarding -various field types supported by the library.<br><br> - -Field names can be up to ten bytes in length and can contain characters, numbers -or special characters in the name. The field methods are used to manipulate -the data in a record of a data file. There are several types of fields.<br><br> - - -<TABLE BORDER> -<CAPTION ALIGN="TOP"><h3>Field Types</H3></CAPTION> -<TR VALIGN="BASELINE"> -<TR><TH ALIGN="LEFT">Type<TD>Size<TD>Allowable Values<TD>Schema Value -<TR><TH ALIGN="LEFT">Numeric<TD>0 - 17(include sign and decimal point<TD>+ - . 0 through 9<TD>XB_NUMERIC_FLD -<TR><TH ALIGN="LEFT">Character<TD>0 - 254<TD>Anything<TD>XB_CHAR_FLD -<TR><TH ALIGN="LEFT">Date<TD>8<TD>CCYYMMDD<TD>XB_DATE_FLD -<TR><TH ALIGN="LEFT">Floating Point<TD>0 - 17 (includes sign and decimal point<TD>+ - . 0 through 9<TD>XB_FLOAT_FLD -<TR><TH ALIGN="LEFT">Logical<TD>1<TD>? Y y N n T t F f (? - uninitialized)<TD>XB_LOGICAL_FLD -<TR><TH ALIGN="LEFT">Memo<TD>Fixed length portion - 10<br>Variable length 0 - 32760 -<TD>Type III - Text<br>Type IV - Anything<TD>XB_MEMO_FLD -</TABLE> - -<br><br> -Field names, types and lengths are defined when a data file is created. -After the file is created, the field characteristics can not be changed. To -change field characteristics, a new database table must be defined with the new -field requirements.<br><br> - -<h2>Memo Fields</h2> - -Memo fields are variable length data fields which are stored in two parts. -This first part is a ten byte field which is stored -in the fixed length record of the .DBF file. The variable data is stored in -a seperate .DBT file in 512 byte blocks. The ten byte field in the fixed -length portion of the record points to a .DBT block number.<br><br> - -There are two versions of memo data files type III and type IV. Type IV -is more advanced in that released space can be reused and it also -supports BLOB data. The type III file is older technology, does not -support dynamic space reclamation and only supports string data. -See method xbDbf::SetVersion for controlling which version type you are -using. - -<br><br> -To utilize memo fields, the application program must allocate a buffer -which is large enough to handle the memo data.<br><br> - -<h2>Fields and Field Numbers</h2> - -The Xbase routines can access field data via using field names or field -numbers. Field numbers are numbered 0-n where the first field in a datafile -is field 0 going through the last field n. Accessing fields by number is -slightly more efficient than accessing by name.<br><br> - -<h2>Strings</h2> - -Xbase64 includes support for a string class <em>xbString</em>. -The xbString class interface was originally derived from the -<em>Draft Standard C++ Library by P.J. Plauger</em> and modified. -If you are familiar with other string classes, this one should be similar. -Strings can be used to manage strings of character data. -<br><br> -<hr> -<p><img src="xbase.jpg"><hr> -</BODY> -</HTML> |