c++builder XE
官方demo最全60多个
http://community.embarcadero.com/blogs?view=entry&id=8761
FireDAC.Comp.Client
用好FDMemTable代替之前的ClientDataSet，以前ClientDataSet内存表转换太繁琐了步骤。
TClientDataSet *cds = new TClientDataSet(this);
DataSetProvider1->DataSet = dm->ADOQueryPub;
cds->ProviderName = "DataSetProvider1";
cds->Open();
c++智能指针
#include <memory> //For STL auto_ptr class
std::auto_ptr<TFDMemTable> table (new TFDMemTable(NULL));
for (table->First(); !table->Eof; table->Next())
{
table->FieldByName("aa")->AsString;
}
一句就可以了
FDMemTable1->CopyDataSet(dm->ADOQueryPub, TFDCopyDataSetOptions() << coStructure << coRestart << coAppend);
多用FDMemTable，不再用ClientDataSet\DataSetProvider1做转换了
FDMemTable2->Data = FDMemTable1->Data;
FDMemTable2->CopyDataSet(FDMemTable1, TFDCopyDataSetOptions() << coStructure << coRestart << coAppend);
建立缓存表
FDMemTable1.Close(); FDMemTable1.FieldDefs.Clear(); FDMemTable1.FieldDefs.Add('ID', ftInteger, 0, True); FDMemTable1.FieldDefs.Add('Name', ftString, 20, false); FDMemTable1.CreateDataSet(); FDMemTable1.AppendRecord([101, 'aaa']); FDMemTable1.AppendRecord([102, 'bbb']); FDMemTable1.AppendRecord([103, 'ccc']);
0）FDMemTable1.SourceView遍历各行数据，取任意行数据无需Next移动指针了。TFDDatSView
for (int i = 0; i < FDMemTable1->SourceView->Rows->Count; i++)
{
Caption = FDMemTable1->SourceView->Rows->ItemsI[i]->GetData(1);
}
FDMemTable1->SourceView->Rows->ItemsI[i]->GetData("fieldName");//取指定行指定字段名的值
}
9行7列的值。
FDMemTable1.Data.DataView.Rows.ItemsI[9].ValueI[7];
FDMemTable1.Table.Rows[i].ValueI[oCol.Index]
Caption = FDMemTable1->SourceView->Rows->Count;//过滤后1条
Caption = FDMemTable1->Table->Rows->Count;//过滤无效，全部记录3条
iMax := 0; for i := 0 to FDQuery1.SourceView.Rows.Count - 1 do if FDQuery1.SourceView.Rows[i].GetData('id', @iVal) and (iVal > iMax) then iMax := iVal
数据集拷贝，复制数据集，合并数据集
FDMemTable1->Filter = "id=102";
FDMemTable1->Filtered = true;
FDMemTable1只有1条记录
1）Data
FDMemTable2->Data = FDMemTable1->Data;
FDQuery->Open("select * from tt");
FDMemTable2->Data = FDQuery->Data;
FDMemTable2是全部记录，有3条记录。
FDMemTable1->Delete();后的记录不在Data里。
2）CopyDataSet
带结构拷贝
FDMemTable2->CopyDataSet(FDMemTable1, TFDCopyDataSetOptions() << coStructure << coRestart << coAppend);
FDMemTable2->CommitUpdates();
缓存更新用到changeCount，所以copy完后加上CommitUpdates
不带结构，仅拷贝数据，字段个数可以不一致，字段数以目标数据集FDMemTable2为标准。
FDMemTable2->CopyDataSet(FDMemTable1, TFDCopyDataSetOptions() << coRestart << coAppend);
//第二个参数默认是coRestart << coAppend，所以下面就更简单了。
FDMemTable2->CopyDataSet(FDMemTable1);
FDMemTable2只有1条记录
3)CopyRecord\CopyField
copy the current record field values .Only One Record
FDMemTable2->CopyDataSet(FDMemTable1, TFDCopyDataSetOptions() << coStructure);
FDMemTable2->Edit();
FDMemTable2->CopyRecord(FDMemTable1);
4)CloneCursor
All Record, ignore filter
CloneCursor，数据共享，一个修改，另一个也修改了，但是FDMemTable1->Close之后FDMemTable2还正常显示。
FDMemTable2->CloneCursor( FDMemTable1);
2016.3.4 test 不能排序，FDMemTable2->IndexFieldNames = "ID";不起作用，所以尽量不建议用这个方式。
5)AtrachTable
All Record,ignore filter,TFDDatSTable
FDMemTable2->AttachTable(FDMemTable1->Table, NULL);
//or
//FDMemTable2->AttachTable(FDMemTable1->Table,FDMemTable1->View);
FDMemTable2->Open();
6)FilteredData
FDQuery1.Filter := 'upper(name) like ''D%'''; FDQuery1.Filtered := True; // copy to FDMemTable1 all FDQuery1 visible (where name starts from D) records FDMemTable1.Data := FDQuery1.FilteredData;
RecordCount是过滤后的记录数。过滤前有100行，过滤后有5行，那么RecordCount就是5
FDQuery1->Data是100行，FilteredData是5行的数据
7)XMLData
All Record ignore filter
Memo1->Text = FDMemTable1->XMLData;
FDMemTable2->XMLData = Memo1->Text;
FDMemTable1->ChangeCount，
通过Data赋值，默认全部记录都是修改过的，也就是ChangeCount=RecordCount，有100条记录，获取ChangeCount属性就是100.这样合适还是不合适呢？
FDMemTable1->Data = FDQuery->Data;
FDMemTable1->CancelUpdates();或者FDMemTable1->CommitUpdates();
加上CancelUpdates这句话，ChangeCount就正常了！！反应真实的修改记录数。
Append的记录需要把属性CachedUpdates设为true，ChangeCount就正确了。
8)Delta
IFDDataSetReference类型
FDMemTable2->Delta= FDMemTable1->Delta;
ADMemTable1.FilterChanges := [rtModified, rtInserted, rtDeleted];
ADMemTable1.Data := ADQuery1.Delta;
9)查看删除过的记录UpdateStatus
FDMemTable想要找到并显示删除的记录
FDMemTable1->Delete();
FDMemTable2->FilterChanges << Firedac::Comp::Dataset::rtDeleted;
FDMemTable1->Data = FDMemTable1->Data;
while (!FDMemTable1.eof)
{
if( table->UpdateStatus() == usDeleted)
...
}
默认是不显示删除过的记录的，FilterChanges不包括rtDeleted属性。
10)分页及加载全部页
FetchOptions的Mode默认是fmOnDemand表示分页，每页50，改为fmAll表示全部记录。
分页TFDFetchOptions.RowsetSize
FetchNext
FetchAll
FetchOptions.RecordCountMode property
FDQuery1.Open;
FDQuery1.FetchAll;//必须加这一句，否则数据集不全。
FDMemTable1.Data := FDQuery1.Data;
用了grideh，为何导致分页不灵了？？？全部记录出来了？field设置了ftsum导致，不设置每次就50行记录。
LocateEx
11）增强的Locate功能LocateEx、LookupEx函数
lxoCheckOnly If included, then LocateEx does not:
Change the current position. Fire BeforeScroll / AfterScroll events. Finish editing mode
不改变位置和编辑状态的搜索，强大！
if (ds1->LocateEx("DM", "001", TFDDataSetLocateOptions() << lxoCheckOnly))
12）刷新数据集
query1.Refresh();
13）只读字段
select '' as temp,flag=0,sql返回的虚拟字段，以前clientDataSet可以修改，FDMemTable里不能改了。
ClientDataSet1->FieldByName("flag")->AsString="1";
但是FDMemTable不能改了。怎么办？以前的这种虚拟字段的方式挺好用啊。
解决办法：设置属性TFDMemTable.UpdateOptions.CheckReadonly=true
14）主从表关系
第一步：
fdqueryDetail.MasterSource := DataSource1;
第二步：
fdqueryDetail.MasterFields := 'OrderNo'; { 多个字段时用分号隔开 }
或者
fdqueryDetail.sql.text='select * from OrderDetail where OrderMasterKey=:OrderMasterKey';
两个FDMemTable做主从怎么不起作用呢？
15）过滤数据FilterChanges
只显示修改后的数据
ClientDataSet1->FilterChanges = TFDUpdateRecordTypes() << Firedac::Comp::Dataset::rtModified;
ClientDatSet用Grideh可以排序，添加EhLibCDS.pas文件即可。
TFDMemTable添加EhLibFireDAC.pas怎么不起不能排序，报错TFDMemTable is not SQL based dataset，FDQuery排序可以了
把SortLocal=true，也不能排序,报错 TSQLDatasetFeaturesEh can not sort data in dataset "FDMemTable1" in local mode
TFDMemTable不能排序，ClientDatSet替换为TFDMemTable的进程又得延缓.
比较和跟踪源码，Delphi里TFDMemTable排序正常。c++builder新建一个工程添加内存表和数据也排序正常。
最终解决了，原来是旧的ehlib控件卸载不干净，原来的工程里还有路径和ehlib.lib文件的链接，清除后排序全部OK！
2019.4.1 一个界面A 排序报错TFDMemTable is not SQL based dataset，弹出窗口排序正确，为什么呢，
FDQuery.Fields.DataSet?这也是数据集？
Data.DB.TFields.DataSet
Identifies the dataset to which a TFields object belongs.
A DataTable or a DataView must be supplied. Hint: if that is TFDMemTable, use CreateDataSet or CloneCursor to open dataset
TFDDataSet 基类
fdquery,dbgrideh控件的ftsum字段求和影响
C++Builder 返回数据集
_di_IFDDataSetReference
16)已有数据的FDMemTable添加列，动态添加列
原有数据集,现有数据集,现有字段,原有字段,添加新增选择列
FDMemTable2.FieldDefs := FDMemTable1.FieldDefs;
FDMemTable2.FieldDefs.Add('Test', ftString, 20 { , False } ); // default parameter
FDMemTable2.FieldDefs.Find('Test').Index := 0;
FDMemTable2.CreateDataSet; // or just Open that sets Active to true;
FDMemTable2.CopyDataSet(FDMemTable1);
17)缓存更新
FDMemTable1->ChangeCount
执行了ApplyUpdates或CommitUpdates后ChangeCount变为0
FDMemTable1->ApplyUpdates(0);
C++builder Berlin //Berlin 排序无效 2017.3.12
delphi正常
升序
self.FDMemTable1.IndexFieldNames := 'ID:A';
降序
self.FDMemTable1.IndexFieldNames := 'ID:D';
FDMemTable1->IndexFieldNames = "ID:D";
FDMemTable1->CloneCursor(m->dsModule, true, true);
CloneCurso的数据集均无法用IndexFieldNames排序。用CreateDataSet创建的数据集排序正常！
Data赋值、CopyDataSet后的数据集均排序可以正常。建议不用CloneCursor。
18.修改只读字段
query1.UpdateOptions.AssignedValues = [uvCheckReadOnly]
FDStoredProc1->UpdateOptions->CheckReadOnly = false;
TSQLTimeStampField
ClientDataSet1: Type mismatch for field 'ffdatetimie', expecting: DateTime actual: TimeStamp
TDateTimeField
TDateTime 替换为
TSQLTimeStampField
FMTBcd
ds1: Type mismatch for field 'UNITPRICE', expecting: Float actual: FMTBcd.
TFloatField *ds1UNITPRICE;
TBCDField
替换为
TFMTBCDField
[Amount] numeric(18,0) TFMTBCDField
[PhPrice] decimal(18,4) TBCDField
ff3 decimal(18,3) TFMTBCDField
可能fdquery认为4位小数就设计器添加到字段列表是TBCDField，非4位小数就是TFMTBCDField，包括0 1 2 3 位小数。
19.建立索引
FDQueryRelation.AddIndex('index1','ITEMTYPE;ITEMNOHIS','', []);
FDQueryRelation.IndexName := 'index1';
经过试验证明，filter没有使用索引，支持like表达式
locate和findkey使用了索引，精确定位，要求检索速度快，检验使用
Caching_Updates_
http://docwiki.embarcadero.com/RADStudio/Rio/en/Caching_Updates_(FireDAC)
FDQuery1.CachedUpdates := True; iSavePoint := FDQuery1.SavePoint; try FDQuery1.Append; ... FDQuery1.Post; FDQuery1.Append; ... FDQuery1.Post; FDQuery1.Append; ... FDQuery1.Post; except FDQuery.SavePoint := iSavePoint; end;
FDQuery1.CachedUpdates := True; FDQuery1.Append; ... FDQuery1.Post; FDQuery1.Append; ... FDQuery1.Post; FDQuery1.Append; ... FDQuery1.Post; FDConnection1.StartTransaction; iErrors := FDQuery1.ApplyUpdates; if iErrors = 0 then begin FDQuery1.CommitUpdates; FDConnection1.Commit; end else FDConnection1.Rollback;
var
oErr: EFDException;
...
if FDQuery1.ApplyUpdates > 0 then begin
FDQuery1.FilterChanges := [rtModified, rtInserted, rtDeleted, rtHasErrors];
try
FDQuery1.First;
while not FDQuery1.Eof do begin
oErr := FDQuery1.RowError;
if oErr <> nil then begin
// process exception object
...
end;
FDQuery1.Next;
end;
finally
FDQuery1.FilterChanges := [rtUnmodified, rtModified, rtInserted];
end;
end;
19)AppendData
2个完全一样的数据集合并 AppendData
ADOQuery1->AppendData(ADOQuery2->Data );
不用循环遍历了，一行命令搞定
void __fastcall Tfrm::ds1UpdateError(TDataSet *ASender, EFDException *AException,
TFDDatSRow *ARow, TFDUpdateRequest ARequest, TFDErrorAction &AAction)
{
throw new Exception( AException->Message );
}
20.fdmemtable批量编辑性能优化
http://docwiki.embarcadero.com/RADStudio/Rio/en/TFDMemTable_Questions
例如 Set the following properties LogChanges, FetchOptions, ResourceOptions, and UpdateOptions.
FDMemTable1.LogChanges := False;
FDMemTable1.FetchOptions.RecsMax := 300000; //Sample value
FDMemTable1.ResourceOptions.SilentMode := True;
FDMemTable1.UpdateOptions.LockMode := lmNone;
FDMemTable1.UpdateOptions.LockPoint := lpDeferred;
FDMemTable1.UpdateOptions.FetchGeneratorsPoint := gpImmediate;
Then surround massive edition operations into BeginBatch / EndBatch method calls:
FDMemTable1.BeginBatch;
try
for i := 1 to 1000 do begin
FDMemTable1.Append;
// ...
FDMemTable1.Post;
end;
finally
FDMemTable1.EndBatch;
end;
c#
DataTable dataFee;
DataRow[] drRerr = dataFee.Select("目录类别=''");
复制表有两种方法
DataTable.Clone() 只克隆表结构
DataTable.Copy() 克隆表结构及数据
DataTable dt2 = dt.Clone();
var rows = dataFee.Select("col3>=30", "col3 desc");
if (rows != null && rows.Length > 0)
{
foreach (DataRow row in rows)
{
dt2.ImportRow(row);
}
}
FDConnection1一句话执行SQL
FDConnection1.ExecSQL('truncate table tab1'); FDConnection1.ExecSQL('drop table tab2', True); FDConnection1.ExecSQL('delete from mytab where id > :p1', [1000]); FDConnection1.ExecSQL('update mytab where id = :p1 set blobfld = :blb', [1000, StringOfChar('x', 100000)], [ftInteger, ftBLOB]);
多表查询更新
FDQuery1->UpdateOptions->UpdateTableName="T_USER_B";//联合查询 更新指定的表
FDQuery1->FieldByName("NAME")->ProviderFlags.Clear();//不更新该字段
克隆
FClonedDataSet := Table.FDataSet.GetClonedDataSet(True);
if FClonedDataSet = nil then begin
FClonedDataSet := TFDMemTable.Create(nil);
TFDMemTable(FClonedDataSet).CopyDataSet(Table.FDataSet, [coStructure, coCalcFields,
coRestart, coAppend, coIndexesCopy, coConstraintsCopy, coAggregatesCopy]);
