EM412 Using Adaptive Server Anywhere with Visual Basic Ali Chalhoub Technical Support Consultant iAnywhere Solutions [email protected]

EM412

Using Adaptive Server Anywhere with Visual Basic

Ali ChalhoubTechnical Support ConsultantiAnywhere [email protected]

Using Adaptive Server Anywhere with Visual Basic

• Visual Basic and its Three Data Interfaces.• ADO Programming Using Adaptive Server Anywhere

OLE DB Provider.• Working with Blobs.• Authenticate a Visual Basic Application.• Introduction to Windows CE.• Summary.

Visual Basic and its Three Data Interfaces

Visual Basic has three methods to establish a connection with a database. These methods are:

• DAO• RDO• ADO


• DAO (Data Access Object)• DAO was the first data access technology

introduced in Visual Basic. It is used to access desktop databases or remote databases.

• RDO (Remote Data Object)• RDO is used to access remote databases. It is

designed to work with client/server databases such as Adaptive Server Anywhere.


• ADO (ActiveX Data Object)• ADO is an application programming interface to OLE

DB. OLE DB is a low-level interface to all types of data. That’s why it is called Universal Data Access (UDA).

• OLE DB is a data access model from Microsoft. It uses

Component Object Model (COM) interfaces that

provide applications with uniform access to data stored

in diverse information sources.


• Why use ADO?• What is ADO Control?• How to Bind Data-Bound Control to an ADO Data

Control?

Why Use ADO?

• Easy-to-use interface for data access.• Current technology• Low memory overhead, small footprint, high speed

and ease of use.

Connection Flow

VB Application

DAO ADO

ODBC Direct

RDO

ODBC

ASA

MS OLE DBProvider

ASA OLE DBProvider

Jet

ADO Data Control

• The ADO data control uses Microsoft ADO to quickly create connections between data-bound controls and data providers.

• Data-bound controls are any controls that feature a DataSource property.• TextBox• Labels• PictureBox• ListBox

Using ADO Data Control

To add the ADO Data

control to the toolbox

• Select Components from the Project menu.

Using ADO Data Control

• Select Microsoft ADO Data Control 6.0 (OLE DB).

Setting up an ADO Data Control

Once the ADO Data control is

added to the toolbox, the following

should be done.

• Add the ADO control to your form.

• Set the ConnectionString property.

ADO Data Control

ADO Data ControlAdded to the Form

Configuring an ADO Data Control

To establish a connection from an ADO Data Control to

Adaptive Server Anywhere database at design time, the

following should be done:• Right click the ADO control and select ADODC

Properties.

Three data source options are available to use.• Use Data Link File.• Use ODBC Data Source Name.• Use Connection String.


• Click on the dropdown list for “Use ODBC Data Source Name”.• Select ASA 7.0 Sample.

Connection Flow

VB Application

ADO

ODBC

ASA

MS OLE DBProvider

ASA OLE DBProvider


• Click on the RecordSource tab.• Select adCmdTable.

ASA Engine


• Select customer table from the “Table or Stored Procedure Name” option.

• Click on Apply.• Click on OK.

Binding a TextBox Control

Once the ADO properties are set correctly, you can

bind a data bound control to show data.

• Add a textbox control to the form where the ADO control was added and set the following properties:• Set DataSource to “Adodc1”.• Set DataField to “fname”.

Binding a TextBox Control

1) DataSource 2) DataField

Displaying Data

Once all the controls are bounded, you should be able to navigate through.

Where Are We?

• Visual Basic and its Three Data Interfaces.• ADO Programming Using Adaptive Server

Anywhere OLE DB Provider.• Working with Blobs.• Authenticate a Visual Basic Application.• Introduction to Windows CE.• Summary.

Adaptive Server Anywhere OLE Provider

• Introduction to ASA OLE DB Provider.• Advantage of using ASA OLE DB Provider.• Supported Platforms.• Registry Entry.• ADO Programming with Adaptive Server

Anywhere.

Introduction to ASA OLE DB Provider

Adaptive Server Anywhere includes an OLE DB provider

named ASAProv. This provider is available for windows

and windows CE.

Adaptive Server Anywhere can also be accessed through

Microsoft’s OLE DB provider, MSDASQL, to be used with

the Adaptive Server Anywhere ODBC Driver.



Anywhere.

Advantage of Using ASA OLE DB Provider

Why using Adaptive Server Anywhere is better than

Using Microsoft’s generic OLE DB provider?

• No need to use ODBC in your deployment if ASA OLE DB provider is used.

• Bookmark is supported when Dynamic cursor is used.

• Recordcount is supported when Dynamic cursor is used.



Anywhere.

Supported Platform

• The ASA OLE DB provider works with ADOCE 3.0 and later.

• ADOCE 3.0 is included in the new Windows CE 3.0 devices, such as PocketPC.



Anywhere.

Registry Entry

• When the ASAProv provider is installed, it registers itself. The ASAProv is registered under the following key: HKEY_CLASSES_ROOT\ASAProv

• If you change the location of your DLL, you must reregister it

Registry Entry

To register the OLE DB provider:

1. Open a command prompt ( DOS prompt)

2. Change to the directory where the OLE DB provider is installed. (Default C:\Program Files\Sybase\SQL Anywhere 7\win32)

3. Enter the following command to register the provider:

Regsvr32 dboledb7.dll



Anywhere.

ADO Programming with Adaptive Server Anywhere

• Connecting to a database using the connection object.

• Executing statements with the command object.• Working with stored procedures.• Working with Recordset object.

Connecting to a Database Using the Connection Object

In order to connect to

Adaptive Server Anywhere

you must have at least the

user id, password and

provider. Check the following

table:

ConnectionString Value

Provider ASAProv

UID User ID

PWD User Password

ENG Server Name

DBF Database File

DBN Database Name

Links=tcpip{} host=x.x.x.x

DSN Data Source Name

Connecting to a Database with the Connection Object

Before the connection can be

established, a reference to the

ADO library must be set. To set the

reference to the library.

The following should be done:

• Select References from the Project Menu.

• Set a reference to the Microsoft ActiveX Data Object 2.x Library (i.e ActiveX Data Object 2.6 ).

Connecting to a Database with the Connection Object

Option Explicit

Dim adoConn as new ADODB.connection

Private Sub cmdConnect_Click()

adoConn.Provider = “ASAProv”

adoConn.ConnectionString= “uid=dba;pwd=sql;dbf=“ & app.path & “\asademo.db”

adoConn.Open

End Sub



• Executing statements with the command object.• Working with stored procedures.• Working with Recordset objects.

Executing Statements with the Command Object

Option Explicit

Dim adoConn as new ADODB.connection


Dim adoCmd As New ADODB.Command

Set adoCmd.ActiveConnection = adoConn

adoCmd.CommandText = "INSERT INTO department VALUES(600,'Accounting',1090)"

adoCmd.CommandType = adCmdText

adoCmd.Execute

End Sub

Prepared Statement

• Improved performance• The first time the SQL statement is executed

• it is parsed and the parsed tree is saved in the engine.

• At this point, the optimizer generates the execution plan.

• Correctness of all referenced database objects is verified

• On subsequent calls, this “ground work” does not have to be repeated

Command Object with Prepared Statement

Dim adoCmd As New ADODB.CommandSet adoCmd.ActiveConnection = adoConnadoCmd.CommandText = "UPDATE employee set emp_fname=?, emp_lname=? WHERE emp_id=?"adoCmd.CommandType = adCmdTextadoCmd.Prepared = True

Dim prmEmpFName As New ADODB.ParameterSet prmEmpFName = adoCmd.CreateParameter("EmpFName", adChar, adParamInput, 20,txtFirstName.text)adoCmd.Parameters.Append prmEmpFName

Dim prmEmpLName As New ADODB.ParameterSet prmEmpLName = adoCmd.CreateParameter("EmpLName", adChar, adParamInput, 20,txtLastName.text)adoCmd.Parameters.Append prmEmpLName

Dim prmEmpID As New ADODB.ParameterSet prmEmpID = adoCmd.CreateParameter("EmpID", adInteger, adParamInput, ,val(txtEmpID.text) )adoCmd.Parameters.Append prmEmpID

Command Object with Prepared Statement

Private Sub cmdUpdate_Click()

adoCmd("EmpFName") = txtFirstName.Text

adoCmd("EmpLName") = txtLastName.Text

adoCmd("EmpID") = Val(txtEmpID.Text)

adoCmd.Execute

MsgBox "Successfully Updated!"

End Sub




Working with Stored Procedures

What is a stored procedure?

• Stored procedure is procedure kept in the database itself which can be called from client application.

• Stored procedure provides a way of providing uniform access to functions automatically, as the procedure is held in the database, not in each client application.


CREATE PROCEDURE sp_retrieve_contacts()RESULT(id integer,last_name char(15),first_name char(15),title char(2),street char(30),city char(20),state char(2),zip char(5),phone char(10),fax char(10))

BEGIN

SELECT id,last_name,first_name,title,street,city,state,zip,phone,fax FROM contact ORDER BY contact.id asc;

END


Private Sub cmdExecuteProcedure_Click()

Dim adoRS As New ADODB.Recordset

adoRS.Open "sp_retrieve_contacts", adoConn, adOpenStatic, adLockReadOnly, adCmdStoredProc

adoRS.MoveFirstSet grdData.DataSource = adoRSgrdData.Refresh

End Sub

Error Handling

Private Sub ErrorHandler()Dim adoErr as ADODB.Error

For Each adoErr In adoConn.Errors strErr = strErr & " Description : " & adoErr.Description & vbCrLf & vbCrLf & _ " SQL CODE : " & adoErr.NativeError & vbCrLf & vbCrLf & _ " SQL STATE : " & adoErr.SQLState & vbCrLf

Next

MsgBox strErr, vbCritical + vbOKOnly, "Error Connecting"End Sub




Working with Recordset Object

What is a Recordset?• ADO Recordset is a set of rows.

• ADO Recordset allows you to set the CursorType property, before you open it.

• Check the ASA User’s Guide for “Types of Cursor”


Recordset Open method syntax:

Recordset-object.Open source, ActiveConection, CursorType, LockType,Options

Source It could be in-line SQL, stored procedure or

table name.

ActiveConnection It tells the open method how to access the

database.

CursorType It tells the database what cursor to use when

opening the Recordest.


ADO Cursor Type ADO constant Adaptive Server Anywhere type

Dynamic cursor adOpenDynamic Dynamic scroll cursor

Keyset cursor adOpenKeyset Scroll cursor

Static cursor adOpenStatic Insensitive cursor

Forward only adOpenForwardOnly No-scroll cursor

Cursor Types

• SCROLL cursors remember both rows and row positions within a cursor, so your application can be assured that these positions remain unchanged.

• DYNAMIC SCROLL cursors are more efficient than SCROLL cursors because they store less information. Therefore, use DYNAMIC SCROLL cursors unless you require the consistent behavior of SCROLL cursors.

• INSENSITVE cursors has its membership fixed when it is opened; and a temporary table is created with a copy of all the original rows. Fetching from an INSENSITIVE cursor does not see the effect of any other operation from a different cursor.

• No Scroll cursors restricts fetching operations to fetching the next row or the same row again.

• Check session AM33 regarding cursors.


Recordset Open method syntax:

Recordset-object.Open source, ActiveConection, CursorType, LockType, Options

LockType It specifies the type of locking the database

should use on the record set when editing of

records occurs.

Options It tells the database what type the source is.

(I.e adCmdTable, adCmdText,etc..)


Locking types are:• Optimistic Locking: The lock is done on row by

row basis, when Update is called.• Batch Optimistic Locking: The lock occurs when

UpdateBatch is called.• Pessimistic Locking: The lock is done on the

edited records at the data source.• Read Only Locking: There is no Locking and

the data can’t be changed.• Check session EM407 regarding locking.


Private Sub cmdOpenRecordSet_Click()

On Error GoTo cmdOpenDoubleRecordSet_Err

Call GetEmployeesAndDept

Call LoadEmployeeName

Set adoRS = adoRS.NextRecordset

Call LoadDept

Call CloseRecordSet

Exit Sub

cmdOpenDoubleRecordSet_Err:

Call ErrorHandler

End Sub


CREATE PROCEDURE DBA.GetEmployeesAndDept()

BEGIN

SELECT emp_fname FROM employee;

SELECT dept_name FROM department;

END

Working with Recordset

Private Sub GetEmployeesAndDepat()

On Error GoTo getEmpAndDept_err

Set adoRS = New ADODB.Recordset

adoRS.Open "call GetEmployeesAndDept()", adoConn, adOpenStatic, adLockReadOnly, adCmdText

Exit Sub

getEmpAndDept_err:

Call ErrorHandler

End Sub

Private Sub LoadEmployeeName() lstEmployee.Clear Do While Not adoRS.EOF lstEmployee.AddItem adoRS!emp_fname adoRS.MoveNext Loop End Sub

Private Sub LoadDept() lstDept.Clear Do While Not adoRS.EOF lstDept.AddItem adoRS!Dept_name adoRS.MoveNext Loop End Sub

Where Are We?

• Visual Basic and its Three Data Interfaces.• Introduction to OLE DB and ADO.• ADO Programming Using Adaptive Server Anywhere


Working with BLOBS


Private Sub cmdFetchDirect_Click()

If Len(txtPictID.Text) > 0 Then

adors.Open "select id, logo from logos where id =" & CInt(txtPictID.Text), adoconn, adOpenDynamic, adLockOptimistic

If adors.BOF And adors.EOF Then

MsgBox "no record founds"

Else

Set pctImage.DataSource = adors

pctImage.DataField = adors.Fields.Item(1).Name

End If

adors.Close

Set adors = Nothing

End If

End Sub

Private Sub cmdSave_Click()

On Error GoTo showError

If Len(txtpath.Text) <> 0 Then

adocmd.ActiveConnection = adoconn

adocmd.CommandText = " INSERT INTO logos(logo) SELECT xp_read_file('" & txtpath.Text & "' )"

adocmd.Execute

MsgBox "Successfully Inserted"

End If

Exit Sub

showError:

MsgBox "Failed to insert"

End Sub


Private Sub cmdSavedDirect_Click()

Dim bytChunk() As Byte

Open txtpath.Text For Binary As #1

ReDim bytChunk(FileLen(txtpath.Text))

Get #1, , bytChunk()

adors.Open "logos", adoconn, adOpenKeyset, adLockPessimistic, adCmdTable

adors.AddNew

adors!logo.AppendChunk bytChunk

adors.Update

adors.Close

Set adors = Nothing

MsgBox "Successfully Inserted!"

Close #1

End Sub

Working with Long VarChar

Dim strLog As String

Set adoCmd = New ADODB.Command

'Escape Character

‘Replace(txtDoc.Text, " ' ", " ' ' ", , , vbTextCompare)

strLog = Replace(txtDoc.Text, "'", "''", , , vbTextCompare)

adoCmd.ActiveConnection = adoConn

adoCmd.CommandText = "INSERT INTO logs(lognote, logdate) VALUES('" & strLog & "','" & Format(clnDate.Value, "mm-dd-yyyy") & "')"

adoCmd.CommandType = adCmdText

adoCmd.Execute

• Saving data of type Long VarChar

Replace(expression, find, replace[, start[, count[, compare]]])

Where Are We?



Authentication

• The Authenticated Edition of ASA is provided for Sybase Commercial Application Partners.

• Applications that use the authenticated engine/server, and are not authenticated, are limited in the functions they can carry out.

• Every connection must be authenticated and has thirty second grace period before the restrictions apply.

• Authentication is not a security device.

Authentication

Authentication

Function Authenticate(tempadoConn As ADODB.Connection) As Boolean Dim adoCmd As New ADODB.Command adoCmd.CommandText = ConnectionSignature adoCmd.CommandType = adCmdText adoCmd.ActiveConnection = tempadoConn adoCmd.Execute Authenticate = TrueEnd Function

Const ConnectionSignature As String = "SET TEMPORARY OPTION CONNECTION_AUTHENTICATION='Company=Sybase;Application=BlobsTech;Signature=000fa55157edb8e14d818eb4fe3db41447146f1571g533e0aa19a7cb78153e4…'"

SET OPTION PUBLIC.DATABASE_AUTHENTICATION='Company=Sybase;Application=BlobsTech;Signature=010fa55157edb8e14d818eb4fe3db41447146f1571g0b8e0330…'

VB

DB

VB

Connection

Where Are We?


OLE DB Provider.• Working with Blobs.• Authenticate a Visual Basic Application.• Introduction to ADOCE.• Summary.

Introduction to ADOCE

• What is ADOCE?• ADOCE Programming with Adaptive Server

Anywhere.

What is ADOCE?

• ADOCE is a subset of ADO.

• Microsoft has released a new IDE, eVB, to develop for Windows CE.


• Connecting to an ASA Engine.• Creating Recordsets.• Navigating Recordsets.

Connecting to an ASA Engine

1. Create a DSN file.

2. Place the DSN on the root of the CE device.

3. Create the connection string.

[ODBC]

uid=dba

pwd=sql

enginename=blob

databasename=blob

databasefile=\image\blob.db

start=\program files\sybase\asa\dbsrv7.exe

Image.dsn

Connecting to ASA Engine


If (ConnectToSybaseDatabase("image")) Then MsgBox "Connected Successfully!"End If

End Sub

Connecting to ASA Engine

Option Explicit

Dim Connection

Function ConnectToSybaseDatabase(DSNname)

'Create the ADOCE connection object

Set Connection = CreateObject("ADOCE.connection.3.1")

'Open the ASA provider

Connection.Open "Provider=ASAProv;Data Source=" & DSNname

ConnectToSybaseDatabase = True

End Function

Working with Recordset on CE

Dim RecSet

Private Sub FetchData()

Set RecSet = CreateObject("ADOCE.RecordSet.3.1")RecSet.Open "call sp_retrieve_contacts()", Connection, adOpenKeyset, adLockReadOnly, adCmdText

RecSet.MoveFirstCall loadData

End Sub

Navigating Recordsets

Private Sub loadData()

txtfname.Text = RecSet.Fields(“first_name”).Valuetxtlname.Text = RecSet.Fields(“last_name”).ValuetxtAddress.Text = RecSet.Fields(“street”).Value

End If

Private Sub cmdPrevious_Click()RecSet.MovePreviousIf RecSet.BOF Then RecSet.MoveNextEnd IfCall loadDataEnd Sub

Private Sub cmdNext_Click()

RecSet.MoveNext

If RecSet.EOF Then

RecSet.MovePrevious

End If

Call loadData

End Sub

Error Handler

• VBCE doesn’t allow you to have goto label.• ADOCE doesn’t allow you to loop through your error object.

On Error Resume Next

If Err.Number <> 0 then MsgBox “ Error : “ & Err.NumberErr.Clear

End If

Summary

• ADO, DAO and RDO are the three methods to connect to a desktop or network server database.

• ASA provider has benefit over the Microsoft provider.

• Authentication engine requires every connection to be authenticated.

• ASA supports ADO and ADOCE.

• ADOCE doesn’t support bound control property.

• ADOCE is different from the ADO error handler.

Documents

EM412 Using Adaptive Server Anywhere with Visual Basic Ali Chalhoub Technical Support Consultant iAnywhere Solutions [email protected]