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<TITLE>BDE API Examples (DbiDoRestructurex)</TITLE>
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<h2>BDE API Examples (DbiDoRestructure)</h2>
Changes the properties of a table.
<hr size=2 noshade>
<H3>Example 1: Add a validity check to the specified field.</H3>
The field must be a longint, and the TTable must be open. This example uses
the following input:<BR>
<I>fDbiDoRestructure(Table4, Table4.Fields[0], @Min, @Max, nil, True)</I> NOTE: This input works for the EMPLOYEE.DB table.
<PRE>procedure fDbiDoRestructure(Tbl: TTable; Field: TField; MinVal, MaxVal,
DefVal: pLongint; Required: Bool);
var
hDb: hDbiDb;
TblDesc: CRTblDesc;
VChk: pVChkDesc;
Dir: String;
NumVChks: Word;
OpType: CROpType;
begin
NumVChks := 0;
SetLength(Dir, dbiMaxNameLen + 1);
Check(DbiGetDirectory(Tbl.DBHandle, False, PChar(Dir)));
SetLength(Dir, StrLen(PChar(Dir)));
VChk := AllocMem(sizeof(VChkDesc));
try
FillChar(TblDesc, sizeof(CRTblDesc), #0);
VChk.iFldNum := Field.Index + 1;
Tbl.DisableControls;
Tbl.Close;
Check(DbiOpenDatabase(nil, nil, dbiReadWrite, dbiOpenExcl,
nil, 0, nil, nil, hDb));
Check(DbiSetDirectory(hDb, PChar(Dir)));
with VChk^ do
begin
bRequired := Required;
if MinVal <> nil then
begin
Inc(NumVChks);
bHasMinVal := True;
move(MinVal^, aMinVal, sizeof(MinVal^));
end
else
bHasMinVal := False;
if MaxVal <> nil then
begin
Inc(NumVChks);
bHasMaxVal := True;
move(MaxVal^, aMaxVal, sizeof(MaxVal^));
end
else
bHasMaxVal := False;
if DefVal <> nil then
begin
Inc(NumVChks);
bHasDefVal := True;
move(DefVal^, aDefVal, sizeof(DefVal^));
end
else
bHasDefVal := False;
end;
TblDesc.iValChkCount := NumVChks;
TblDesc.pVChkDesc := VChk;
OpType := crADD;
TblDesc.pecrValChkOp := @OpType;
StrPCopy(TblDesc.szTblName, Tbl.TableName);
StrCopy(TblDesc.szTblType, szParadox);
Check(DbiDoRestructure(hDb, 1, @TblDesc, nil, nil, nil, False));
finally
Check(DbiCloseDatabase(hDb));
FreeMem(VChk, sizeof(VChkDesc));
Tbl.EnableControls;
Tbl.Open;
end;
end;</PRE>
<!-- SF -->
<HR SIZE=2 NOSHADE>
<A NAME="Ex2"></A>
<H3>Example 2: Pack a Paradox or dBASE table.</H3>
This example will pack a Paradox or dBASE table therfore removing already
deleted rows in a table. This function will also regenerate all out-of-date
indexes (maintained indexes) This example uses the following input:<BR>
<I>PackTable(Table1)</I>
<PRE>// Pack a Paradox or dBASE table
// The table must be opened execlusively before calling this function...
procedure PackTable(Table: TTable);
var
Props: CURProps;
hDb: hDBIDb;
TableDesc: CRTblDesc;
begin
// Make sure the table is open exclusively so we can get the db handle...
if Table.Active = False then
raise EDatabaseError.Create('Table must be opened to pack');
if Table.Exclusive = False then
raise EDatabaseError.Create('Table must be opened exclusively to pack');
// Get the table properties to determine table type...
Check(DbiGetCursorProps(Table.Handle, Props));
// If the table is a Paradox table, you must call DbiDoRestructure...
if Props.szTableType = szPARADOX then
begin
// Blank out the structure...
FillChar(TableDesc, sizeof(TableDesc), 0);
// Get the database handle from the table's cursor handle...
Check(DbiGetObjFromObj(hDBIObj(Table.Handle), objDATABASE, hDBIObj(hDb)));
// Put the table name in the table descriptor...
StrPCopy(TableDesc.szTblName, Table.TableName);
// Put the table type in the table descriptor...
StrPCopy(TableDesc.szTblType, Props.szTableType);
// Set the Pack option in the table descriptor to TRUE...
TableDesc.bPack := True;
// Close the table so the restructure can complete...
Table.Close;
// Call DbiDoRestructure...
Check(DbiDoRestructure(hDb, 1, @TableDesc, nil, nil, nil, FALSE));
end
else
// If the table is a dBASE table, simply call DbiPackTable...
if Props.szTableType = szDBASE then
Check(DbiPackTable(Table.DBHandle, Table.Handle, nil, szDBASE, TRUE))
else
// Pack only works on PAradox or dBASE; nothing else...
raise EDatabaseError.Create('Table must be either of Paradox or dBASE ' +
'type to pack');
Table.Open;
end;</PRE>
<!-- SF -->
<HR SIZE=2 NOSHADE>
<H3>Example 3: Alter a field in a Paradox or dBASE table.</H3>
This example will alter an existing field in a Paradox or dBASE table.<BR>
NOTE: You must fill in all options in the ChangeRec with 0 or '' if the option is
not used in the restructure. FillChar can be used to do this: Fillchar(MyChangeRec,
sizeof(MyChangeRec), 0);<BR>
This example uses the following input:<BR>
<I>ChangeField(Table1, Table1.FieldByName('FOO'), MyChangeRec)</I><BR>
ChangeRec is defind as follows:
<PRE>ChangeRec = packed record
szName: DBINAME;
iType: word;
iSubType: word;
iLength: word;
iPrecision: byte;
end;</PRE>
The function is defined as follows:
<PRE>procedure ChangeField(Table: TTable; Field: TField; Rec: ChangeRec);
var
Props: CURProps;
hDb: hDBIDb;
TableDesc: CRTblDesc;
pFields: pFLDDesc;
pOp: pCROpType;
B: byte;
begin
// Initialize the pointers...
pFields := nil; pOp := nil;
// Make sure the table is open exclusively so we can get the db handle...
if Table.Active = False then
raise EDatabaseError.Create('Table must be opened to restructure');
if Table.Exclusive = False then
raise EDatabaseError.Create('Table must be opened exclusively to restructure');
Check(DbiSetProp(hDBIObj(Table.Handle), curxltMODE, integer(xltNONE)));
// Get the table properties to determine table type...
Check(DbiGetCursorProps(Table.Handle, Props));
// Make sure the table is either Paradox or dBASE...
if (Props.szTableType <> szPARADOX) and (Props.szTableType <> szDBASE) then
raise EDatabaseError.Create('Field altering can only occur on Paradox' +
' or dBASE tables');
// Allocate memory for the field descriptor...
pFields := AllocMem(Table.FieldCount * sizeof(FLDDesc));
// Allocate memory for the operation descriptor...
pOp := AllocMem(Table.FieldCount * sizeof(CROpType));
try
// Set the pointer to the index in the operation descriptor to put
// crMODIFY (This means a modification to the record is going to happen)...
Inc(pOp, Field.Index);
pOp^ := crMODIFY;
Dec(pOp, Field.Index);
// Fill the field descriptor with the existing field information...
Check(DbiGetFieldDescs(Table.Handle, pFields));
// Set the pointer t
Delphi API使用手册
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Delphi API使用手册 （105个子文件） 
dbidorestructure.html 36KB dbiopencfginfolist.html 17KB dbicreatetable.html 10KB dbiwriteblock.html 8KB dbiaddindex.html 8KB dbiopenfieldlist.html 7KB dbiopenvchklist.html 7KB dbiopenrintlist.html 5KB dbiregistercallback.html 5KB dbigetprop.html 5KB dbigetsysversion.html 5KB dbicreatetemptable.html 4KB dbiisrecordlocked.html 4KB dbiacqpersisttablelock.html 4KB dbisorttable.html 4KB dbiqgetbasedescs.html 4KB dbiopenldlist.html 4KB dbiopenuserlist.html 4KB dbicopytable.html 3KB dbiopendatabase.html 3KB dbiopentable.html 3KB dbiemptytable.html 3KB dbigeterrorentry.html 3KB dbireltablelock.html 3KB dbisetprop.html 3KB dbisetfieldmap.html 3KB dbiacqtablelock.html 3KB dbigetcursorprops.html 3KB dbiaddalias.html 3KB dbibeginlinkmode.html 3KB dbiuseidletime.html 3KB dbistartsession.html 3KB dbigetrecord.html 3KB dbirelrecordlock.html 3KB dbiqexec.html 3KB dbiclosesession.html 3KB dbiopenfieldtypeslist.html 3KB dbiaddpassword.html 3KB dbiaddfilter.html 3KB dbiregenindex.html 3KB dbipacktable.html 3KB dbiistablelocked.html 3KB dbiopendatabaselist.html 3KB dbigetfielddescs.html 3KB dbisavechanges.html 3KB dbireadblock.html 3KB dbiopentablelist.html 3KB dbicomparebookmarks.html 3KB dbiopenfilelist.html 3KB dbiforcerecordreread.html 3KB dbigetrecordcount.html 3KB dbigetldname.html 3KB dbicheckrefresh.html 3KB dbigeterrorinfo.html 3KB dbiopendriverlist.html 3KB dbigetdatabasedesc.html 3KB dbiqexecdirect.html 3KB dbigetclientinfo.html 3KB dbigetnetusername.html 3KB dbigetseqno.html 3KB dbidropfilter.html 3KB dbiopenindexlist.html 3KB dbiclonecursor.html 3KB dbigeterrorcontext.html 3KB dbiopentabletypeslist.html 3KB dbiextractkey.html 3KB dbigetindexforfield.html 3KB dbideletealias.html 3KB dbigetindexdesc.html 3KB dbisettoseqno.html 3KB dbisetrange.html 3KB dbisettorecordno.html 3KB dbiopenlocklist.html 3KB dbigetldobj.html 3KB dbiansitonative.html 3KB dbirelpersisttablelock.html 3KB dbigetcursorfortable.html 3KB dbiclosedatabase.html 3KB dbiforcereread.html 3KB dbiendlinkmode.html 3KB dbisettokey.html 3KB dbisetcurrsession.html 3KB dbigetcurrsession.html 3KB dbisetlockretry.html 3KB dbigettimeformat.html 3KB dbisettobegin.html 3KB dbigetnumberformat.html 3KB dbigetdirectory.html 3KB dbigetdateformat.html 3KB dbiregenindexes.html 3KB dbisettoend.html 3KB dbiunlinkdetail.html 3KB dbidebuglayeroptions.html 3KB dbisetdateformat.html 3KB dbiformfullname.html 3KB dbigetsesinfo.html 3KB dbigetsysconfig.html 3KB dbigetdriverdesc.html 3KB dbigetindexdescs.html 3KB dbigetsysinfo.html 3KB共 105 条
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资源评论
liangyunyou3152012-11-21解压后全是当个的网页文件，英文的，感觉不好
cohye2015-09-11英文的资料，只有认真研究了。
CDSN_SB_SYY2015-11-30都不知道这个怎么用，我是菜鸟
