Though auditing has become a popular buzzword, many DBAs and developers still do not appreciate the requirement for auditing. Properly implemented, auditing can achieve the below:

In this Article I want to describe you how we can approach a data base free data layer.

It doesn't mean that we will not use anydatabase, but we will try to incorporate any data source with our datalayer. This kind of problem happen when we are not sure about eitherdata source/Database will be Oracle, SQLServer, Access, etc.

An advantage having with this approach is when data source changes there is no single line change in our database layer.

Scope

C#, VB.NET, Visual Basic, Java (Both Desktop and web)

Implementation of Data Access Layer

Let me describe whatever approaches I havetried to solve this problem. First I thought I have to use Interfacelevel communication rather than implementation as we were doing inpast.

Rather than using Sqlconnection, Oledbconnection, SqlCommand, OledbCommand etc.

For connection
- DbConnection.
For Command
- IDbCommand.

One problem solves of specific connection andcommand objects. Another problem is how I should tell my data accesslayer to retrieve parameter for stored procedure. Because if I write inthe code then our problem is remain we have to modify the data accesslayer after any data source changes.

Then I have to introduce a file which can be modified on runtime and then ready to another data source.

I introduced an Xml file for this.

<objectMapping type="ForTestAuthentication">
<!–table name–>
<operation name="DbInsert" fname="tested">
<!–operation name–>
<command name="LoginCheck" spnumber="0">
<!–stored procedure name–>
<parameterMappings>
<parameter name="@username" member="aspnet_Users" type="varchar" length="50" direction="input"/>
</parameterMappings>
</objectMapping>

Class Diagram

Class Code

For Generic connection and command I use factory method to get the generic connection irrespective of any data source.

private static IDbConnection GetConnectionFromFactory(string strDBProvider, string strDBConnectionString, IDbConnection objIdbConnection)
{
switch (strDBProvider)
{
case _SQLSERVER:
{
objIdbConnection = new SqlConnection(strDBConnectionString);
break;
}
case _ORACLE:
{
objIdbConnection = new OleDbConnection(strDBConnectionString);
break;
}
case _OTHER:
{
objIdbConnection = new OleDbConnection(strDBConnectionString);
break;
}
}
return objIdbConnection;
}

Similarly for I have to apply this generic theme to all of my ADO.net objects.

public static IDataParameter[] GetParameter(int parmaterCount)
{
IDataParameter[] idbParamters = null;
if (parmaterCount > 0)
{

switch (/*ConfigurationSettings.AppSettings["providerName"]*/"sqlserver")
{
case _SQLSERVER:
{
idbParamters = new SqlParameter[parmaterCount];
break;
}
case _ORACLE:
{
idbParamters = new OleDbParameter[parmaterCount];
break;
}

case _OTHER:
{
idbParamters = new OleDbParameter[parmaterCount];
break;
}
}
}
return idbParamters;
}

And same operation with DataCommand Objects.There are some comments on ConfigurationSettings.AppSettings.Because Iwas using this in dll and I cann.t access theConfigurationSettings.AppSettings object. But we can use any way aroundon it. Anyhow this is not our point of discussion here.

public static IDbCommand GetIDBCommand()
{
IDbCommand objIdbComand = null;

switch (/*ConfigurationSettings.AppSettings["providerName"]*/"sqlserver")
{
case _SQLSERVER:
{
objIdbComand = new SqlCommand();
break;
}
case _ORACLE:
{
objIdbComand = new OleDbCommand();
break;
}

case _OTHER:
{
objIdbComand = new OleDbCommand();
break;
}
}

return objIdbComand;
}

We can pass our stored procedure code andobject value array. We have a utility method through which we canaccess the stored procedure name and it.s collection of parameters.

There is one thing very strictly follow thatyou have to pass object value array in same sequence of the parameteras you have defined in the stored procedure in the database. Thisstored procedure parameters sequence is also reflecting in theconfigXml file.

Retrieving stored procedure information form Configuration file

XmlNodeList xnlstParamtercollection = xnode.SelectNodes("parameterMappings/parameter");

if (xnlstParamtercollection != null && xnlstParamtercollection.Count > 0)
{
IDBParameter = DataProvider.GetParameter(parameterValues.Length);
int paramcounter = 0;
foreach (XmlNode name in xnlstParamtercollection)
{
IDBParameter[paramcounter] = DataProvider.GetParameterInstance();
IDBParameter[paramcounter].ParameterName = name.SelectNodes("@name").Item(0).InnerXml;
IDBParameter[paramcounter].Value = parameterValues[paramcounter];

if (name.SelectNodes("@direction").Item(0).InnerXml == DEFAULT_PARATMER_DIRECTION)
IDBParameter[paramcounter].Direction = ParameterDirection.Input;

else
IDBParameter[paramcounter].Direction = ParameterDirection.Output;
objIdbCommand.Parameters.Add(IDBParameter[paramcounter]);

paramcounter++;
}
}

There is also possibility that you canretrieve the parameter collection from the SQLServer directly .Butanyway this is working fine. Because here is our main intention isdatabase free DAL.

Specialized parameter retrieving mechanism for SQLServer

But now consider the scenario when we havespecially data source SQLServer. Then we have to use this functionwhich is not including in my code but you can consider it.

private static SqlParameter[]

DiscoverSpParameterSet(SqlConnection connection, string spName, bool includeReturnValueParameter)
{
if( connection == null ) throw new ArgumentNullException( "connection" );
if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );

SqlCommand cmd = new SqlCommand(spName, connection);
cmd.CommandType = CommandType.StoredProcedure;

connection.Open();
SqlCommandBuilder.DeriveParameters(cmd);
connection.Close();

if (!includeReturnValuePa
rameter)

{
cmd.Parameters.RemoveAt(0);
}

SqlParameter[] discoveredParameters = new SqlParameter[cmd.Parameters.Count];

cmd.Parameters.CopyTo(discoveredParameters, 0);

// Init the parameters with a DBNull value
foreach (SqlParameter discoveredParameter in discoveredParameters)
{
discoveredParameter.Value = DBNull.Value;
}
return discoveredParameters;
}

I will try my best to improve this article innext version because truly speaking this is an idea how we canimplement this Database frees DataAccessLayer. But I am sure when youpeople read it then you can also incorporate your ideas in it or youcan give me suggestion which is very helpful for me.

Future Development

This bit is pretty much up to you guys, if anyone makes any valid suggestions I'd be more than happy to implement them.

History

Version 1.0 (02 September 2007) – Initial Release

About Nazish Ali Rizvi

Hi, I am Nazish Ali I did my Master of Computer Science from Karachi University.Primary Programming Language is C# .My other hobbies Reading philosophy, poetry.

It is a sample C# (VS2005) application forAutomatic Sql server Backup Utility using sqlserveragent. I have usedSQL-DMO dll. This article will show you how to create a automaticbackup in Sql server 2000.

This code should work on any PC use VB.NET and installed SQL Server 2000 (any edition or Client Components for SQL Server 2000.

SQLDMO (Which installed always bt MS SQL Server 2000 or MS SQL Server Client Tools

To do:

1) First Enter Your Sql Server username and password on corresponding Text Box
2) Set backup Start date & Backup Time
3) After Finishing this then please check manually it will working or not
4) Manual working procedure:
1) Run Sql sever enterprise Manager
2) Select management Option
3) Open Sql server agent
4) Open Jobs window
5) Check whether job item exist or not
6) Right click on newly created job item then, we will get one
7) Popup menu, then select start job
After finish the job then check folder "D:backup" bkp file created or not

Important Functions

Add reference to SQL-DMO dll

You can do this by right clicking the projectin Solution Explorer, then selecting 'Add Reference', COM componentsand the latest version of "Microsoft SQLDMO Object Library".

Available Server

public void dIsplayServerList(ComboBox cboListName)
{
try
{
SQLDMO.Application oSQLServerDMOApp = new SQLDMO.Application();
Info.informationLayer info = new Info.informationLayer();

SQLDMO.NameList oNameList;
oNameList = oSQLServerDMOApp.ListAvailableSQLServers();
for (int intIndex = 0; intIndex <= oNameList.Count – 1; intIndex++)
{
if (oNameList.Item(intIndex as object) != null)
{
cboListName.Items.Add(oNameList.Item(intIndex).ToString());
}
}
if (cboListName.Items.Count > 0) cboListName.SelectedIndex = 0;
else cboListName.Text = "(Local)";
}
catch
{

}

Available databases

public void dIsplayDatabases(ComboBox cboDatabase,Info.informationLayer info)
{
try
{
SQLDMO._SQLServer SQLServer = new SQLDMO.SQLServerClass();

cboDatabase.Items.Clear();
SQLServer.Connect(info.strServerName,info.strLoginName,info.strPwd);
foreach (SQLDMO.Database db in SQLServer.Databases)
{
if (db.Name != null)
cboDatabase.Items.Add(db.Name);
}
cboDatabase.Sorted = true;
if (cboDatabase.Items.Count == 0)cboDatabase.Text = "<no>";
}
catch (Exception err)
{
info.ErrorMessageDataLayer = err.Message;

}
}

Create Job on Server Agent :

public void CreateJob_Sql(Info.informationLayer info)
{
{
try
{
SQLDMO._SQLServer SQLServer = new SQLDMO.SQLServerClass();
SQLDMO.Job SQLJob = new SQLDMO.Job();
SQLDMO.JobSchedule SQLSchedule = new SQLDMO.JobSchedule();

SQLServer.Connect(info.strServerName, info.strLoginName, info.strPwd);

switch (SQLServer.JobServer.Status)
{
case SQLDMO_SVCSTATUS_TYPE.SQLDMOSvc_Stopped:
SQLServer.JobServer.Start();
SQLServer.JobServer.AutoStart = true;
break;
}

SQLJob.Name = info.strDatabaseName;
SQLJob.Description = "Check and Backup" + info.strDatabaseName;

SQLServer.JobServer.Jobs.Add(SQLJob);
SQLJob.Category = "Database Maintenance";

SQLDMO.JobStep aJobStep = new SQLDMO.JobStep();

aJobStep.Name = "Step 2: Backup the Database";
aJobStep.StepID = 1;

aJobStep.DatabaseName = info.strDatabaseName;

aJobStep.SubSystem = "TSQL";
//——>>> If BackUp Folder is Not Found then create BackUp Folder.

string DirectoryName = "D:BackUp";
if (Directory.Exists(DirectoryName)==false)
{
System.IO.Directory.CreateDirectory(DirectoryName);
}
//——>>>
string sExt;
sExt="EXEC master.dbo.xp_sqlmaint '-S " + info.strServerName + " -U " + info.strLoginName + " -P " +
info.strPwd + " -D " + info.strDatabaseName + " -CkDB -CkAl -CkCat -BkUpMedia DISK -BkUpDB D:Backup -BkExt BAK -DelBkUps
2weeks -BkUpOnlyIfClean -Rpt D:BackupBackDB_Checks.txt'";
aJobStep.Command = sExt;
aJobStep.OnSuccessAction = SQLDMO_JOBSTEPACTION_TYPE.SQLDMOJobStepAction_QuitWithSuccess;
aJobStep.OnFailAction = SQLDMO_JOBSTEPACTION_TYPE.SQLDMOJobStepAction_QuitWithFailure;
SQLJob.JobSteps.Add(aJobStep);
SQLJob.ApplyToTargetServer(info.strServerName);
aJobStep.DoAlter();
SQLJob.Refresh();
aJobStep.Refresh();

}
catch (Exception Err)
{
info.ErrorMessageDataLayer = Err.Message;
}
}
}
</no>

Create Job shedule on server Agent:

public void CreateShedule_Sql(Info.informationLayer info)
{
try
{
//it will take bkp every week 2 day
SQLDMO.Job SQLJob = new SQLDMO.Job();

SQLDMO._SQLServer SQLServer = new SQLDMO.SQLServerClass();
SQLDMO.JobSchedule SQLSchedule = new SQLDMO.JobSchedule();

SQLServer.Connect(info.strServerName, info.strLoginName, info.strPwd);
SQLJob = SQLServer.JobServer.Jobs.Item(info.strDatabaseName);

// create a new JobSchedule object
SQLSchedule.Name = "Weekly Backup";
SQLSchedule.Schedule.FrequencyType = SQLDMO.SQLDMO_FREQUENCY_TYPE.SQLDMOFreq_Weekly;
SQLSchedule.Schedule.FrequencyInterval = 2;
SQLSchedule.Schedule.FrequencyRecurrenceFactor = 2;

// // start on Feb18, 2000 – at 12.55
SQLSchedule.Schedule.ActiveStartDate = info.intStartDate;
SQLSchedule.Schedule.ActiveStartTimeOfDay = info.intStartTime;
//// this schedule has no end time or end date

SQLSchedule.Schedule.ActiveEndDate = 99991231;
SQLSchedule.Schedule.ActiveEndTimeOfDay = 235959;

//// add the schedule to the Job
SQLJob.BeginAlter();
SQLJob.JobSchedules.Add(SQLSchedule);
SQLJob.DoAlter();
//SQLJob.JobSchedules.Refresh();
info.ErrorMessageDataLayer = "New Sql Job [Databasename= " + info.strDatabaseName + " ]Sucessfully Created. ";
}
catch (Exception err)
{
info.ErrorMessageDataLayer = err.Message;

}
}

Syntax (SQL Server 2000)
xp_sqlmaint 'switch_string'
[
[-S server_name[instance_name]]
[-U login_ID [-P password]]
{
[ -D database_name | -PlanName name | -PlanID guid ]
[-Rpt text_file]
[-To operator_name]
[-HtmlRpt html_file [-DelHtmlRpt <time_period>] ]
[-RmUnusedSpace threshold_percent free_percent]
[-CkDB | -CkDBNoIdx]
[-CkAl | -CkAlNoIdx]
[-CkCat]
[-UpdOptiStats sample_percent]
[-RebldIdx free_space]
[-WriteHistory]
[
{-BkUpDB [backup_path] | -BkUpLog [backup_path] }
{-BkUpMedia
{DISK [ [-DelBkUps <time_period>]
[-CrBkSubDir ] [ -UseDefDir ]
]
| TAPE
}
}
[-BkUpOnlyIfClean]
[-VrfyBackup]
]
}
]

time_period
number[minutes | hours | days | weeks | months]

Syntax (SQL Server 7.0)
sqlmaint
[-?] |
[
[-S server] /> [-U l
ogin_ID [-P password]]
{
[ -D database_name | -PlanName name | -PlanID guid ]
[-Rpt text_file [-DelTxtRpt <time_period>] ]
[-To operator_name]
[-HtmlRpt html_file [-DelHtmlRpt <time_period>] ]
[-RmUnusedSpace threshold_percent free_percent]
[-CkDB | -CkDBNoIdx]
[-CkAl | -CkAlNoIdx]
[-CkTxtAl]
[-CkCat]
[-UpdSts]
[-UpdOptiStats sample_percent]
[-RebldIdx free_space]
[-WriteHistory]
[
{-BkUpDB [backup_path] | -BkUpLog [backup_path] }
{-BkUpMedia
{DISK [ [-DelBkUps <time_period>]
[-CrBkSubDir ] [ -UseDefDir ]
]
| TAPE
}
}
[-BkUpOnlyIfClean]
[-VrfyBackup]
]
}
]
</time_period></time_period></time_period></time_period></time_period>

Download dbMaintain.zip

Tdo Is Open Source

From this version (2.0), Tdo has become anopen source project and both the source code and the setup package aredownloadable from sourceforge.net at the following web address:http://tdo.sourceforge.net.The setup package installs both the base library Tdo.dll and the sourcecode generator TdoCodeGenerator.exe.To be able to use it it's recommended to have already installed both MSVisual Studio .NET 2005 and Sql Server 2005 (or EXPRESS/2000/7/MSDE).

[continued]

Note: This demo connects to an SQL Server anduses the Northwind database. You need to modify the App.config to makethis demo work.

Here iss the C# sample.

using System;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;

namespace SortingDataTables
{
/// <summary>
/// Summary description for Class1.
/// </summary>
class MainClass
{
/// <summary>
/// The main entry point for the application.
/// </summary>
[STAThread]
static void Main(string[] args)
{
// declare a dataview and assign it the values from GetEmployeesUnsorted()
DataView dvUnsorted = GetEmployeesUnsorted();
Console.WriteLine("+++++ Unsorted Dataview ++++++");
//call our print function
PrintToConsole(dvUnsorted,"LastName");

// declare a dataview and assign it the values from GetEmployeesSorted()
DataView dvSorted = GetEmployeesSorted();
Console.WriteLine("+++++ Sorted Dataview ++++++");
//call our print function
PrintToConsole(dvSorted,"LastName");

// declare a dataview and assign it the values from GetEmployeesWithFilter()
DataView dvFiltered = GetEmployeesWithFilter();
Console.WriteLine("+++++ Filtered Dataview ++++++");
//call our print function
PrintToConsole(dvFiltered,"LastName");

//pause
Console.ReadLine();

}

private static void PrintToConsole(DataView dv, string columnName)
{
//loop thru the dataview
for(int i =0; i < dv.Count; i++)
{
//print the value in index i from the specified column
Console.WriteLine(dv[i][columnName].ToString());
}
}

private static DataView GetEmployeesSorted()
{
//get the connection string from app.config
string connectionString = ConfigurationSettings.AppSettings["ConnectionString"];
//create a new connection and assign our connection string
SqlConnection sqlConnection = new SqlConnection(connectionString);
//create a new command and pass our sql statement and our connection object.
SqlCommand sqlCommand = new SqlCommand("Select Lastname from Employees",sqlConnection);

//open the connection
sqlConnection.Open();

//create a new sqladapter and set its command object with our sqlcommand
SqlDataAdapter sqlAdapter = new SqlDataAdapter(sqlCommand);
//create a new dataset to hold our data
DataSet ds = new DataSet();
//fill the dataset with the result of our query from the specified command
sqlAdapter.Fill(ds);

//create a new dataview from our table in our dataset at index 0
DataView dv = new DataView(ds.Tables[0]);

//apply a sort
dv.Sort = "Lastname Desc";

//close our connection
sqlConnection.Close();

//return our dataview
return dv;
}

private static DataView GetEmployeesUnsorted()
{
//get the connection string from app.config
string connectionString = ConfigurationSettings.AppSettings["ConnectionString"];
//create a new connection and assign our connection string
SqlConnection sqlConnection = new SqlConnection(connectionString);
//create a new command and pass our sql statement and our connection object.
SqlCommand sqlCommand = new SqlCommand("Select Lastname from Employees",sqlConnection);

//open the connection
sqlConnection.Open();

//create a new sqladapter and set its command object with our sqlcommand
SqlDataAdapter sqlAdapter = new SqlDataAdapter(sqlCommand);
//create a new dataset to hold our data
DataSet ds = new DataSet();
//fill the dataset with the result of our query from the specified command
sqlAdapter.Fill(ds);

//create a new dataview from our table in our dataset at index 0
DataView dv = new DataView(ds.Tables[0]);

//close our connection
sqlConnection.Close();

//return our dataview
return dv;

}

private static DataView GetEmployeesWithFilter()
{
//get the connection string from app.config
string connectionString = ConfigurationSettings.AppSettings["ConnectionString"];
//create a new connection and assign our connection string
SqlConnection sqlConnection = new SqlConnection(connectionString);
//create a new command and pass our sql statement and our connection object.
SqlCommand sqlCommand = new SqlCommand("Select Lastname from Employees",sqlConnection);

//open the connection
sqlConnection.Open();

//create a new sqladapter and set its command object with our sqlcommand
SqlDataAdapter sqlAdapter = new SqlDataAdapter(sqlCommand);
//create a new dataset to hold our data
DataSet ds = new DataSet();
//fill the dataset with the result of our query from the specified command
sqlAdapter.Fill(ds);

//create a new dataview from our table in our dataset at index 0
DataView dv = new DataView(ds.Tables[0]);

//apply our row filter. get only records with a lastname of 'Callahan'
dv.RowFilter = "LastName = 'Callahan'";

//close our connection
sqlConnection.Close();

//return our dataview
return dv;
}
}
}

Here's the VB.NET sample.

Imports System.Data
Imports System.Data.SqlClient
Imports System.Configuration

Module MainModule

Sub Main()

' declare a dataview and assign it the values from GetEmployeesUnsorted()
Dim dvUnsorted As DataView = GetEmployeesUnsorted()
Console.WriteLine("+++++ Sorted Dataview ++++++")
'call our print function
PrintToConsole(dvUnsorted, "LastName")

' declare a dataview and assign it the values from GetEmployeesSorted()
Dim dvSorted As DataView = GetEmployeesSorted()
Console.WriteLine("+++++ Sorted Dataview ++++++")
'call our print function
PrintToConsole(dvSorted, "LastName")

' declare a dataview and assign it the values from GetEmployeesWithFilter()
Dim dvFiltered As DataView = GetEmployeesWithFilter()
Console.WriteLine("+++++ Filtered Dataview ++++++")
'call our print function
PrintToConsole(dvFiltered, "LastName")

Console.ReadLine()
End Sub

Private Sub PrintToConsole(ByVal dv As DataView, ByVal columnName As String)
'loop thru the dataview
For i As Integer = 0 To dv.Count – 1
'print the value in index i from the specified column
Console.WriteLine(dv(i)(columnName).ToString())
Next
End Sub

Private Function GetEmployeesSorted() As DataView
'get the connection string from app.config
Dim connectionString As String = ConfigurationSettings.AppSettings("ConnectionString")
'create a new connection and assign our connection string
Dim sqlConnection As SqlConnection = New SqlConnection(connectionString)
'create a new command and pass our sql statement and our connection object
Dim sqlCommand As SqlCommand = New SqlCommand("Select Lastname from Employees", sqlConnection)

'open the connection
sqlConnection.Open()

'create a new sqladapter and set its command object with our sqlcommand
Dim sqlAdapter As SqlDataAdapter = New SqlDataAdapter(sqlCommand)
'create a new dataset to hold our data
Dim ds As Dat

aSet = N
ew DataSet
'fill the dataset with the result of our query from the specified command
sqlAdapter.Fill(ds)

'create a new dataview from our table in our dataset at index 0
Dim dv As DataView = New DataView(ds.Tables(0))

'apply a sort
dv.Sort = "Lastname Desc"

'close our connection
sqlConnection.Close()
'return our dataview
Return dv
End Function

Private Function GetEmployeesUnsorted() As DataView
'get the connection string from app.config
Dim connectionString As String = ConfigurationSettings.AppSettings("ConnectionString")
'create a new connection and assign our connection string
Dim sqlConnection As SqlConnection = New SqlConnection(connectionString)
'create a new command and pass our sql statement and our connection object
Dim sqlCommand As SqlCommand = New SqlCommand("Select Lastname from Employees", sqlConnection)

'open the connection
sqlConnection.Open()

'create a new sqladapter and set its command object with our sqlcommand
Dim sqlAdapter As SqlDataAdapter = New SqlDataAdapter(sqlCommand)
'create a new dataset to hold our data
Dim ds As DataSet = New DataSet
'fill the dataset with the result of our query from the specified command
sqlAdapter.Fill(ds)

'create a new dataview from our table in our dataset at index 0
Dim dv As DataView = New DataView(ds.Tables(0))

'close our connection
sqlConnection.Close()
'return our dataview
Return dv
End Function

Private Function GetEmployeesWithFilter() As DataView
'get the connection string from app.config
Dim connectionString As String = ConfigurationSettings.AppSettings("ConnectionString")
'create a new connection and assign our connection string
Dim sqlConnection As SqlConnection = New SqlConnection(connectionString)
'create a new command and pass our sql statement and our connection object
Dim sqlCommand As SqlCommand = New SqlCommand("Select Lastname from Employees", sqlConnection)

'open the connection
sqlConnection.Open()

'create a new sqladapter and set its command object with our sqlcommand
Dim sqlAdapter As SqlDataAdapter = New SqlDataAdapter(sqlCommand)
'create a new dataset to hold our data
Dim ds As DataSet = New DataSet
'fill the dataset with the result of our query from the specified command
sqlAdapter.Fill(ds)

'create a new dataview from our table in our dataset at index 0
Dim dv As DataView = New DataView(ds.Tables(0))

'apply our row filter. get only records with a lastname of 'Callahan'
dv.RowFilter = "LastName = 'Callahan'"

'close our connection
sqlConnection.Close()
'return our dataview
Return dv
End Function

End Module

Here is the App.Config for both project

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
<appSettings>
<add key="ConnectionString"
value="server=[yourserver];database=Northwind;uid=[username];pwd=[password];" />
</appSettings>
</configuration>

Download SortingDataTables.zip