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<h2>BDE API Examples (DbiAddIndex)</h2>
Creates an index on an existing table.
<hr size=2 noshade>
<p>
<b>Add an index to a Paradox 4.0 or 5.0 version table:
</b><DD>This example is included with Delphi in the BDE32.HLP file.
<p>
<b>Add an index to a Paradox 4.0 or 5.0 version table:
</b><DD>This example is included with Delphi in the BDE32.HLP file.
<p>
<b>Add an index to a Paradox 7.0 version table:
</b><DD>This example is included with Delphi in the BDE32.HLP file.
<p>
<b>Add an index to a dBASE for Windows version table:
</b><DD>This example is included with Delphi in the BDE32.HLP file.
<p>
<b> Add an expression index to a dBASE for Windows version table:
</b><DD>This example is included with Delphi in the BDE32.HLP file.
<hr size=2 noshade>
<h3>Example 1: Create a maintained, case insensitive index on the first and
second fields on a Paradox tables. The first field of the index is
descending and the second is ascending.</h3>
This example uses the following input:<BR> <I>fDbiAddIndex6(Table1)</I>
<PRE>Procedure fDbiAddIndex6(Tbl: TTable);
var
NewIndex: IDXDesc;
begin
FillChar(NewIndex, SizeOf(NewIndex), 0);
if Tbl.Exclusive = False then
raise EDatabaseError.Create
('TTable.Exclusive must be set to true in order to add an index to the table');
NewIndex.szName:= 'NewIndex2';
NewIndex.iIndexId:= 0;
NewIndex.bPrimary:= FALSE;
NewIndex.bUnique:= FALSE;
NewIndex.bDescending:= TRUE;
NewIndex.bMaintained:= TRUE;
NewIndex.bSubset:= FALSE;
NewIndex.bExpIdx:= FALSE;
NewIndex.iFldsInKey:= 2;
NewIndex.aiKeyFld[0]:= 1;
NewIndex.aiKeyFld[1]:=2;
NewIndex.abDescending[0]:=TRUE;
NewIndex.abDescending[1]:=FALSE;
NewIndex.bCaseInsensitive:= TRUE;
Check(DbiAddIndex(Tbl.dbhandle, Tbl.handle, PChar(Tbl.TableName),
szParadox, NewIndex, nil));
end;</PRE>
<!-- QW -->
<hr size=2 noshade>
<h3>Example 2: Create a maintained, expression index with a subset filter.</h3>
This example uses the following input:<BR> <I>AddExpFilter(Table1, 'OUTRISK',
'STR(OUTLOOK)+RISK', 'RISK=''HIGH''');</I><BR>
NOTE: You can use this input with the master.dbf table in the delphi/demos/data directory.
<PRE>procedure AddExpFilter(Table: TTable; TagName, Expression, Filter: string);
var
NewIndex: IDXDesc;
begin
if TagName = '' then
raise EDatabaseError.Create('A tag name must be supplied to create an expression index');
if Expression = '' then
raise EDatabaseError.Create('A expression be supplied to create an index');
if Table.exclusive = False then
raise EDatabaseError.Create('Table: ' + Table.Tablename + ' must be opened exclusively ' +
'to create an index');
FillChar(NewIndex, sizeof(NewIndex), 0);
StrPCopy(NewIndex.szTagName, TagName);
NewIndex.bPrimary:= False;
NewIndex.bUnique:= False;
NewIndex.bDescending:= False;
NewIndex.bMaintained:= True;
if Filter = '' then
NewIndex.bSubset:= False
else
NewIndex.bSubset:= True;
NewIndex.bExpIdx:= True;
StrPCopy(NewIndex.szKeyExp, Expression);
StrPCopy(NewIndex.szKeyCond, Filter);
NewIndex.bCaseInsensitive:= False;
Check(DbiAddIndex(Table.dbhandle, Table.handle, PChar(Table.TableName),
szParadox, NewIndex, nil));
end;</PRE>
<!-- SF, 10/9/97 -->
<hr size=2 noshade>
<h3>Example 3: Create a multi-field secondary index on a Paradox table.</h3>
This example uses the following input:<BR> <I>AddMultiFieldIndex(Table2, 'Multi', False,
[Table2.Fields[0], Table2.Fields[2], Table2.Fields[1]]);</I><BR>
<PRE>procedure AddMultiFieldIndex(Table: TTable; IndexName: string; Unique: boolean;
const Fields: array of TField);
var
NewIndex: IDXDesc;
b: byte;
Props: CURProps;
begin
// Make sure an index name is supplied...
if IndexName = '' then
raise EDatabaseError.Create('An index name must be supplied');
// Make sure the table is opened exclusively...
if Table.exclusive = False then
raise EDatabaseError.Create('Table: ' + Table.Tablename +
' must be opened exclusively to create an index');
Check(DbiGetCursorProps(Table.Handle, Props));
// Make sure the table is of type PARADOX...
if StrComp(Props.szTableType, szPARADOX) <> 0 then
raise EDatabaseError.Create('Table must be of type PARADOX');
FillChar(NewIndex, sizeof(NewIndex), 0);
StrPCopy(NewIndex.szName, IndexName);
NewIndex.bUnique := Unique;
NewIndex.bMaintained := True;
// Set the field mappings for the multi field index...
NewIndex.iFldsInKey := sizeof(Fields) div sizeof(TField);
for b := 0 to NewIndex.iFldsInkey - 1 do
NewIndex.aiKeyFld[b] := Fields[b].Index + 1;
// Create the index...
Check(DbiAddIndex(Table.dbhandle, Table.handle, nil, nil, NewIndex, nil));
end;
</PRE>
<!-- SF, 3/3/98 -->
<hr size=2 noshade>
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