Delphi (Tuxedo, BDE, ADO) three-in-one dataset component HsTxQuery and tuxedohstxquery

Delphi (Tuxedo, BDE, ADO) three-in-one dataset component HsTxQuery and tuxedohstxquery

Delphi (Tuxedo, BDE, ADO) three-in-one dataset component HsTxQuery

I. background

Why is this three-in-one dataset component required? In the past, most of the systems developed by our company using delphi were connected to databases using ADO and BDE. These two sets of components were very convenient and flexible to use and cost control friendly, from the usage in the past 10 years, it seems that the problem is not big, and users do not have a three-tier architecture requirement. However, when bidding for large companies this year, the project is often blocked by technical requirements. Why? Party A's bidding documents contain a three-tier architecture, which is a headache for us. Currently, our company uses Tuxedo as the middle layer. If it is transformed, the cost is expected to be one year, the maintenance cost of the two versions is also very high. In the face of this situation, I propose a three-in-one approach, that is, building a new dataset component. The new component is compatible with all the attributes and methods of the previous Query. You only need to use the UE editor to replace the previous Query Class and switch between the Tuxedo, BDE, and ADO connection methods, the system does not need to maintain another version. I hope you will be grateful for your advice.

Ii. Component Structure

From the structure diagram, we can see that the decoration mode is used. HsTxQuery places the user's access object behind it and forwards it to different objects based on the connection mode. It accesses Tuxedo through HsTxQuery. dll, with a layer of conversion in the middle, while BDE and ADO are directly connected.

Iii. Design

 

Iv. Example

1. Open

Procedure TForm1.Button7Click (Sender: TObject ); Begin HsQuery2.close; HsQuery2. SQL. Text: = 'select * from users '; HsQuery2.Open; End;

 

2. Execute

Procedure TForm1.Button7Click (Sender: TObject ); Begin HsQuery2.close; HsQuery2. SQL. Text: = 'insert test value (1, 2, 3 )'; HsQuery2. ExecSQL; End;

 

3. insert records

Procedure TForm1.Button9Click (Sender: TObject ); Var MS: TMemoryStream; Begin MS: = TMemoryStream. Create; Image2.Picture. Graphic. SaveToStream (MS ); With HsQuery2 do Begin Database. StartTransaction; Append; HsQuery2.FieldByName ('f1'). AsString: = FormatDateTime ('yyyymmddhhmmss ', now ); HsQuery2.FieldByName ('F2'). AsString: = FormatDateTime ('yyyymmdd', now ); HsQuery2.FieldByName ('f3 '). AsString: = FormatDateTime ('hhmmss', now ); HsQuery2.FieldByName ('F4'). AsString: = 'chic go '; HsQuery2.FieldByName ('f5'). AsString: = '1 '; HsQuery2.FieldByName ('f6 '). AsString: = '000000 '; HsQuery2.FieldByName ('f7 '). AsString: = '1 '; HsQuery2.SetBlobStream (HsQuery2.FieldByName ('fphoto '), MS ); Post; ApplyUpdates; CommitUpdates; Database. Commit; End; Ms. Free; End;

 

4. update records

Procedure TForm1.Button10Click (Sender: TObject ); Var Ms: TMemoryStream; Begin Ms: = TMemoryStream. Create; Image2.Picture. Graphic. SaveToStream (MS ); HsQuery2.Edit; HsQuery2.Fields. Fields [0]. AsString: = '6 '; HsQuery2.Fields. Fields [1]. AsInteger: = 198; HsQuery2.Fields. Fields [2]. AsString: = ''; HsQuery2.Fields. Fields [3]. AsString: = 'roy '; HsQuery2.Fields. Fields [4]. AsString: = '1 '; HsQuery2.Fields. Fields [5]. AsString: = '2 '; HsQuery2.SetBlobStream (HsQuery2.Fields. Fields [6], MS ); HsQuery2.Post; HsQuery2.ApplyUpdates; HsQuery2.CommitUpdates; Ms. Free; End;

 

5. delete records

HsQuery2.Delete;

 

6. Save/retrieve Blob Data

To view the insert example.

Procedure TForm1.Button8Click (Sender: TObject ); Var Stream: TMemoryStream; Jpg: tsf-image; Begin Stream: = HsQuery2.GetBlobStream (HsQuery2.FieldByName ('data ')); Jpg: = tsf-image. Create; Stream. Position: = 0; Jpg. LoadFromStream (Stream); // load the image Image2.Picture. Assign (Jpg ); End;

 

7. Obtain the field value

Procedure TForm1.Button15Click (Sender: TObject ); Begin ShowMessage (hsQuery2.FieldByName ('userid'). AsString ); ShowMessage (hsQuery2.Fields. Fields [0]. AsString ); End;

 

8. Filter

// Filter HsQuery2.Filter: = 'userid = 102 '; HsQuery2.Filtered: = true; // The following is anti-Filtering HsQuery2.Filter: = ''; HsQuery2.Filtered: = true;

 

9. Parameters

/ Procedure TForm1.Button16Click (Sender: TObject ); Begin With hsquery2 do Begin Close; SQL. clear; SQL. Text: = 'select * From users where USERID =: id '; ParamByName ('id'). value: = 106; Open; End; End;

 

10. Dynamic switching of Tuxedo, BDE, and ADO Modes

/ Procedure TForm1.ComboBox1Change (Sender: TObject ); Begin Case combobox1.ItemIndex 0: Begin HsQuery2.DatasetType: = dtTuxedo; HsQuery2.ConnectionString: = '// 192.168.1.121: 8887 '; End; 1: Begin HsQuery2.DatasetType: = dtBDE; HsQuery2.ConnectionString: = 'orcl '; HsQuery2.Connection: = Database1; End; 2: Begin HsQuery2.DatasetType: = dtADO; HsQuery2.ConnectionString: = 'provider = OraOLEDB. Oracle.1; Password = gf; Persist Security Info = True; User ID = gf; Data Source = orcl; Extended Properties = ""'; HsQuery2.Connection: = ADOConnection1; End; End; End;

 

 

V. Outlook

Many data-exchange middleware (such as various MQ) can be encapsulated into easy-to-use components to make the developer's life better.

Control Address: https://sourceforge.net/projects/hstxqueryfordelphi/

Delphi7 ADO and BDE control group missing

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How does the query code of the BDE control in Delphi be converted into the adoquery code in ADO? The Code is as follows:

With ADOQUEYR do
Begin
Close;
ADOQUEYR. parameters [0]. value: = trim (edit1.Text );
ADOQUEYR. parameters [1]. value: = trim (edit2.Text );
ADOQUEYR. parameters [2]. value: = trim ('user ');
Execsql;
In the content of ADOQUEYR, insert into user values (: A,: B,: C) Does the user User table have only three columns?