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Wednesday, October 13, 2010

Inserting & Retrieving records from M.S.Access-2007 using Odbc in C#.net

Objective:          To develop a windows application for performing insert, search, update, delete operations & navigation of M.S.Access 2007 records using Odbc connection.
Introduction:
Create a table in M.S.Access 2007 file and populate it.
In our application we use ‘stud.accdb’ (M.S.Access 2007) file, which consists ‘student’ table.
(Note: ‘stud.accdb’ is placed in ‘prash_access07.zip’ along with source code)

Creating and Configuring ODBC Data Source (dsn):
Go to Start Menu -> Control Panel -> Administrative Tools -> Data Sources (ODBC)





Click on ‘Add’ button
-> Select ‘Microsoft Access Driver (*.mdb, *.accdb)’ ->click on ‘Finish’ button.
Give a name to your Data Source
Click on ‘Select’ button and select your M.S.Access 2007 file (*.accdb) -> OK -> OK
Your Data Source Name will be specified in ‘ODBC Data Source Administrator’ window
->Click on ‘OK’ button.

Thus, your Data Source (dsn) is configured.

Design:


Design the form as above with a DataGridView, 3 Labels, 3 TextBoxes, 10 buttons.


Introduction to Code:

As we want to use Odbc Connection include the namespace:

'using System.Data.Odbc'

For accesing records from M.S.Access-2003 file we use 'Jet' driver,

But for accesing records from M.S.Access-2003 file we use 'Ace' driver.

In this application, we will search a record by taking input from the InputBox. For this we have to add reference to Microsoft.VisualBasic.

Adding a Reference:

Goto Project Menu ->Add Reference -> select 'Microsoft.VisualBasic' from .NET tab.

In order to use this we have to include the namespace:

'using Microsoft.VisualBasic'

Odbc connection string:
Syntax:
OdbcConnection con = new OdbcConnection("dsn=<Data Source Name>");
Ex:
OdbcConnection con = new OdbcConnection(“dsn=myaccess07dsn ");

You just need to specify the Data Source Name(dsn) in the Connection String, no need to specify the driver details and path of the file, you dsn will take care of it.

Creating a primary key in the dataTable:

In this app. we use Find() method to search a record, which requires details of primarykey column for database tables; this is provided using statement:
adapter.MissingSchemaAction = MissingSchemaAction.AddWithKey

But as we don't have any primarykey column in M.S.Access table, we have to create a primary key column in datatable.
Ex:
ds.Tables[0].Constraints.Add("pk_sno", ds.Tables[0].Columns[0], true);

Pointing to current record in dataTable:

After searching a record, we have to get the index of that record so that we can show next and previous records when we press '>>'(next) and '<<'(previous) buttons.
Ex:
rno= ds.Tables[0].Rows.IndexOf(drow);
-------------

Code:
using System;
using System.Data;
using System.Windows.Forms;
using System.Data.Odbc;
using Microsoft.VisualBasic;

namespace prash_access07
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        OdbcConnection con;
        OdbcCommand cmd;
        OdbcDataAdapter adapter;
        DataSet ds;
        int rno;

        private void Form1_Load(object sender, EventArgs e)
        {
            con = new OdbcConnection("dsn=myaccess07dsn");
            //stud.accdb->access07 filename
            loaddata();
            showdata();
        }
        void loaddata()
        {
            adapter = new OdbcDataAdapter("select * from student", con);
            ds = new DataSet();//student-> table name in stud.accdb file
            adapter.Fill(ds, "student");
            ds.Tables[0].Constraints.Add("pk_sno", ds.Tables[0].Columns[0], true);//creating primary key for Tables[0] in dataset
            dataGridView1.DataSource = ds.Tables[0];
        }
        void showdata()
        {
            textBox1.Text = ds.Tables[0].Rows[rno][0].ToString();
            textBox2.Text = ds.Tables[0].Rows[rno][1].ToString();
            textBox3.Text = ds.Tables[0].Rows[rno][2].ToString();
        }
     
        private void btnFirst_Click(object sender, EventArgs e)
        {
            if (ds.Tables[0].Rows.Count > 0)
            {
                rno = 0;
                showdata();
            }
            else
                MessageBox.Show("no records");
        }

        private void btnPrevious_Click(object sender, EventArgs e)
        {
            if (ds.Tables[0].Rows.Count > 0)
            {
                if (rno > 0)
                {
                    rno--;
                    showdata();
                }
                else
                    MessageBox.Show("First Record");
            }
            else
                MessageBox.Show("no records");
        }

        private void btnNext_Click(object sender, EventArgs e)
        {
            if (ds.Tables[0].Rows.Count > 0)
            {
                if (rno < ds.Tables[0].Rows.Count - 1)
                {
                    rno++;
                    showdata();
                }
                else
                    MessageBox.Show("Last Record");

            }
            else
                MessageBox.Show("no records");
        }

        private void btnLast_Click(object sender, EventArgs e)
        {
            if (ds.Tables[0].Rows.Count > 0)
            {
                rno = ds.Tables[0].Rows.Count - 1;
                showdata();
            }
            else
                MessageBox.Show("no records");
        }

        private void btnInsert_Click(object sender, EventArgs e)
        {
            cmd = new OdbcCommand("insert into student values(" + textBox1.Text + ",' " + textBox2.Text + " ',' " + textBox3.Text + " ')", con);
            con.Open();
            int n = cmd.ExecuteNonQuery();
            con.Close();

            if (n > 0)
            {
                MessageBox.Show("record inserted");
                loaddata();
            }
            else
                MessageBox.Show("insertion failed");
        }

        private void btnSearch_Click(object sender, EventArgs e)
        {
            int n = Convert.ToInt32(Interaction.InputBox("Enter sno:", "Search", "20", 200, 200));
            DataRow drow = ds.Tables[0].Rows.Find(n);
            if (drow != null)
            {
                rno = ds.Tables[0].Rows.IndexOf(drow);
                textBox1.Text = drow[0].ToString();
                textBox2.Text = drow[1].ToString();
                textBox3.Text = drow[2].ToString();
            }
            else
                MessageBox.Show("Record not found");
        }

        private void btnUpdate_Click(object sender, EventArgs e)
        {
            cmd = new OdbcCommand("update student set sname='" + textBox2.Text + "',course='" + textBox3.Text + "' where sno=" + textBox1.Text, con);
            con.Open();
            int n = cmd.ExecuteNonQuery();
            con.Close();
            if (n > 0)
            {
                MessageBox.Show("Record Updated");
                loaddata();
            }
            else
                MessageBox.Show("Update failed");
        }

        private void btnDelete_Click(object sender, EventArgs e)
        {
            cmd = new OdbcCommand("delete from student where sno=" + textBox1.Text, con);
            con.Open();
            int n = cmd.ExecuteNonQuery();
            con.Close();
            if (n > 0)
            {
                MessageBox.Show("Record Deleted");
                loaddata();
            }

            else
                MessageBox.Show("Deletion failed");
        }

        private void btnClear_Click(object sender, EventArgs e)
        {
            textBox1.Text = textBox2.Text = textBox3.Text = "";
        }

        private void btnExit_Click(object sender, EventArgs e)
        {
            this.Close();
        }
    
    }
}

Saturday, October 9, 2010

Prashanth Chindam's Blog: inserting & retrieving images from database using ...

Prashanth Chindam's Blog: inserting & retrieving images from database using ...: "Objective: To insert & retrieve images from SQL server database using stored procedures and also to perform insert, search, update ..."

Prashanth Chindam's Blog: inserting & retrieving images from database withou...

Prashanth Chindam's Blog: inserting & retrieving images from database withou...: "Objective: To insert into & retrieve images from SQL server database without using stored procedures and also to perform insert, se..."

inserting & retrieving images from database without using stored procedures

Objective:
          To insert into & retrieve images from SQL server database without using stored procedures and also to perform insert, search, update and delete operations & navigation of records.
Introduction:
As we want to insert images into the database, first we have to create a table in the database, we can use the data type ‘image’ or ‘binary’ for storing the image.
Query for creating table in our application:create table student(sno int primary key,sname varchar(50),course varchar(50),fee money,photo image)
Design:

Design the form as above with 1 PictureBox control, 1 OpenFileDialog control, 4 Labels, 4 TextBoxes and 11 Buttons.
PictureBox1 Properties:
    BorderStyle=Fixed3D; SizeMode=StrechImage
Note that OpenFileDialog control appears below the form(not on the form), which can be used for browsing an image.


Introduction to code:
Inorder to communicate with SQL sever database, include the namespace‘using System.Data.SqlClient’.
In this application, we will search a record by taking input from the InputBox. For this we have to add reference to Microsoft.VisualBasic.
Adding a Reference to ‘Microsoft.VisualBasic’:

Goto Project Menu ->Add Reference -> select 'Microsoft.VisualBasic' from .NET tab.
In order to use this reference we have to include the namespace:
'using Microsoft.VisualBasic' in the code.
Converting image into binary data:
We can’t store an image directly into the database. For this we have two solutions:
i) To store the location of the image in the database
ii) Converting the image into binary data and insert that binary data into database and convert that back to image while retrieving the records.
If we store the location of an image in the database, and suppose if that image is deleted or moved from that location, we will face problems while retrieving the records. So it is better to convert image into binary data and insert that binary data into database and convert that back to image while retrieving records.
->We can convert an image into binary data using 1. FileStream (or) 2. MemoryStream
1. FileStream uses file location to convert an image into binary data which we may/may not provide during updation of a record.
Ex:
      FileStream fs = new FileStream(openFileDialog1.FileName, FileMode.Open,                       FileAccess.Read);
      byte[] photo_aray = new byte[fs.Length];
      fs.Read(photo_aray, 0, photo_aray.Length);

2. So it is better to use MemoryStream which uses image in the PictureBox to convert an image into binary data.
Ex:
             MemoryStream ms = new MemoryStream();
             pictureBox1.Image.Save(ms, ImageFormat.Jpeg);
             byte[] photo_aray = new byte[ms.Length];
             ms.Position = 0;
             ms.Read(photo_aray, 0, photo_aray.Length);
->Inorder to use FileStream or MemoryStream we have to include the namespace:‘using System.IO’.
             OpenFileDialog Control:We use OpenFileDialog control inorder to browse for the images (photos) to insert into the record.
Loading the constraint details into the dataTable:
In this app. we use Find() method to search a record, which requires details of primarykey column, which can be provided using the statement:
adapter.MissingSchemaAction = MissingSchemaAction.AddWithKey;

Pointing to current record in dataTable:
After searching a record, we have to get the index of that record so that we can navigate the next and previous records.
 Ex:
rno= ds.Tables[0].Rows.IndexOf(drow);
-------------

Code:
using System;
using System.Windows.Forms;
using System.Data;
using System.Data.SqlClient;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using Microsoft.VisualBasic;

namespace inserting_imgs
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        SqlConnection con;
        SqlCommand cmd;
        SqlDataAdapter adapter;
        DataSet ds; int rno = 0;
        MemoryStream ms;
        byte[] photo_aray;

        private void Form1_Load(object sender, EventArgs e)
        {
            con = new SqlConnection("user id=sa;password=123;database=prash");
            loaddata();
            showdata();
        }
        void loaddata()
        {
            adapter = new SqlDataAdapter("select sno,sname,course,fee,photo from student", con);
            adapter.MissingSchemaAction = MissingSchemaAction.AddWithKey;
            ds = new DataSet(); adapter.Fill(ds, "student");
        }
        void showdata()
        {
            if (ds.Tables[0].Rows.Count > 0)
            {
                textBox1.Text = ds.Tables[0].Rows[rno][0].ToString();
                textBox2.Text = ds.Tables[0].Rows[rno][1].ToString();
                textBox3.Text = ds.Tables[0].Rows[rno][2].ToString();
                textBox4.Text = ds.Tables[0].Rows[rno][3].ToString();
                pictureBox1.Image = null;
                if (ds.Tables[0].Rows[rno][4] != System.DBNull.Value)
                {
                    photo_aray = (byte[])ds.Tables[0].Rows[rno][4];
                    MemoryStream ms = new MemoryStream(photo_aray);
                    pictureBox1.Image = Image.FromStream(ms);
                }
            }
            else
                MessageBox.Show("No Records");
        }

        private void browse_Click(object sender, EventArgs e)
        {
            openFileDialog1.Filter = "jpeg|*.jpg|bmp|*.bmp|all files|*.*";
            DialogResult res = openFileDialog1.ShowDialog();
            if (res == DialogResult.OK)
            {
                pictureBox1.Image = Image.FromFile(openFileDialog1.FileName);
            }
        }

        private void newbtn_Click(object sender, EventArgs e)
        {
            cmd = new SqlCommand("select max(sno)+10 from student", con);
            con.Open();
            textBox1.Text = cmd.ExecuteScalar().ToString();
            con.Close();
            textBox2.Text = textBox3.Text = textBox4.Text = "";
            pictureBox1.Image = null;
        }

        private void insert_Click(object sender, EventArgs e)
        {
            cmd = new SqlCommand("insert into student(sno,sname,course,fee,photo) values(" + textBox1.Text + ",'" + textBox2.TabIndex + "','" + textBox3.Text + "'," + textBox4.Text + ",@photo)", con);
            conv_photo();
            con.Open();
            int n = cmd.ExecuteNonQuery();
            con.Close();
            if (n > 0)
            {
                MessageBox.Show("record inserted");
                loaddata();
            }
            else
                MessageBox.Show("insertion failed");
        }
        void conv_photo()
        {
            //converting photo to binary data
            if (pictureBox1.Image != null)
            {
                //using FileStream:(will not work while updating, if image is not changed)
                //FileStream fs = new FileStream(openFileDialog1.FileName, FileMode.Open, FileAccess.Read);
                //byte[] photo_aray = new byte[fs.Length];
                //fs.Read(photo_aray, 0, photo_aray.Length); 

                //using MemoryStream:
                ms = new MemoryStream();
                pictureBox1.Image.Save(ms, ImageFormat.Jpeg);
                byte[] photo_aray = new byte[ms.Length];
                ms.Position = 0;
                ms.Read(photo_aray, 0, photo_aray.Length);
                cmd.Parameters.AddWithValue("@photo", photo_aray);
            }
        }

        private void search_Click(object sender, EventArgs e)
        {
            try
            {
                int n = Convert.ToInt32(Interaction.InputBox("Enter sno:", "Search", "20", 100, 100));
                DataRow drow;
                drow = ds.Tables[0].Rows.Find(n);
                if (drow != null)
                {
                    rno = ds.Tables[0].Rows.IndexOf(drow);
                    textBox1.Text = drow[0].ToString();
                    textBox2.Text = drow[1].ToString();
                    textBox3.Text = drow[2].ToString();
                    textBox4.Text = drow[3].ToString();
                    pictureBox1.Image = null;
                    if (drow[4] != System.DBNull.Value)
                    {
                        photo_aray = (byte[])drow[4];
                        MemoryStream ms = new MemoryStream(photo_aray);
                        pictureBox1.Image = Image.FromStream(ms);
                    }
                }
                else
                    MessageBox.Show("Record Not Found");
            }
            catch
            {
                MessageBox.Show("Invalid Input");
            }
        }

        private void update_Click(object sender, EventArgs e)
        {
            cmd = new SqlCommand("update student set sname='" + textBox2.Text + "', course='" + textBox3.Text + "', fee='" + textBox4.Text + "', photo=@photo where sno=" + textBox1.Text, con);
            conv_photo();
            con.Open();
            int n = cmd.ExecuteNonQuery();
            con.Close();
            if (n > 0)
            {
                MessageBox.Show("Record Updated");
                loaddata();
            }
            else
                MessageBox.Show("Updation Failed");
        }

        private void delete_Click(object sender, EventArgs e)
        {
            cmd = new SqlCommand("delete from student where sno=" + textBox1.Text, con);
            con.Open();
            int n = cmd.ExecuteNonQuery();
            con.Close();
            if (n > 0)
            {
                MessageBox.Show("Record Deleted");
                loaddata();
                rno = 0;
                showdata();
            }
            else
                MessageBox.Show("Deletion Failed");
        }

        private void first_Click(object sender, EventArgs e)
        {
            rno = 0; showdata();
            MessageBox.Show("First record");
        }

        private void previous_Click(object sender, EventArgs e)
        {

            if (rno > 0)
            {
                rno--; showdata();
            }
            else
                MessageBox.Show("First record");
        }

        private void next_Click(object sender, EventArgs e)
        {
            if (rno < ds.Tables[0].Rows.Count - 1)
            {
                rno++; showdata();
            }
            else
                MessageBox.Show("Last record");
        }

        private void last_Click(object sender, EventArgs e)
        {
            rno = ds.Tables[0].Rows.Count - 1;
            showdata(); MessageBox.Show("Last record");
        }

        private void exit_Click(object sender, EventArgs e)
        {
            this.Close();
        }        
  
    }
}