What are the steps to connect to a database?

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nishant2200  

  • Member Since Jan-2007 | Jan 7th, 2007


1. Create a connection. This requires a connection string, which can be given declaratively or put in a well defined place like the .config files. Advantage of keeping in .config files is that it enables use of Connection Pooling by .Net framework, else even one small change in connection string will cause CLR to think it's not the same connection and will instantiate new connection for other request.

2. Open the connection and keep it open until done, typically done as using (con) { //use }

3. If using connected data model, create a SqlCommand object, decorate it with desired command, command type (stored procedure for eg), add any parameters and their values to the command, and then consume the command by using ExcuteReader or ExecuteScalar. In case of ExecuteReader, we will get back a handle to a fast-forward, read only pointer to the recordset. We can also decorate Command object with multiple recordsets in 2.0 and execute one by one (MARS - Multiple Active Record Sets)

4. If using disconnected data model, create a DataAdapter object, decorate it with desired SELECT, INSERT, UPDATE, DELETE commands, add parameters as necessary and then fill up a DataSet or DataTable using the DataAdapter. Subsequent  SQL can be executed using insert, update, delete commands on the dataset.

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aman

  • Dec 20th, 2006
 

THere r many steps ;

Create a data adapter & connection & pass query..

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Balli

  • Dec 22nd, 2006
 

1) we need to create a connection string like in example,dbconn.

2)open the connection

3)create your required like in below example,sql

4)create a command object to execute the sql query like dbcomm

5)using Datareader object get the results like dbread

dim dbconn,sql,dbcomm,dbread
dbconn=New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;
data source=" & server.mappath("northwind.mdb"))
dbconn.Open()
sql="SELECT * FROM customers"
dbcomm=New OleDbCommand(sql,dbconn)
dbread=dbcomm.ExecuteReader()

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1. Create a connection. This requires a connection string, which can be given declaratively or put in a well defined place like the .config files. Advantage of keeping in .config files is that it enables use of Connection Pooling by .Net framework, else even one small change in connection string will cause CLR to think it's not the same connection and will instantiate new connection for other request.

2. Open the connection and keep it open until done, typically done as using (con) { //use }

3. If using connected data model, create a SqlCommand object, decorate it with desired command, command type (stored procedure for eg), add any parameters and their values to the command, and then consume the command by using ExcuteReader or ExecuteScalar. In case of ExecuteReader, we will get back a handle to a fast-forward, read only pointer to the recordset. We can also decorate Command object with multiple recordsets in 2.0 and execute one by one (MARS - Multiple Active Record Sets)

4. If using disconnected data model, create a DataAdapter object, decorate it with desired SELECT, INSERT, UPDATE, DELETE commands, add parameters as necessary and then fill up a DataSet or DataTable using the DataAdapter. Subsequent  SQL can be executed using insert, update, delete commands on the dataset.

Hi,


Ans:

Step 1. create a connection string.
     SqlConnection SqlCon=new SqlConnecyion("Connectionstring");   


 Step 2.open the connection.

SqlCon.Open();

Step 3.pass a query through command object

   SqlCommand SqlCom=new SqlCommand("sqlQuries",SqlCon);

Step 4.Read the using datareader.

         Datareader dr=SqlCom.ExcuteReader();
Step 5.Display the data using any display control.

     Like DataGrid or GridView or  DropDownBox,Datalist etc

Step 6.close the connection
  SqlCon.Close()

Thanx all
Here Sahu

Venu

  • Jun 13th, 2007
 

I created oledb connectionString

Dim StaffConnectionString As String = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=|DataDirectory|Staff.mdb"


Dim Conn As New OleDbConnection(StaffConnectionString)


Conn.Open()


Dim myQuery As String = "select Phone2 from tblStaff where Firstname = value"


Dim Cmd As New OleDbCommand(myQuery, Conn)

Dim dbread = Cmd.ExecuteReader()

Here I am getting an exception in ExecuteReader() saying one or more parameters are missing.

Please solve this as quickly as posible

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step 1:
                first we have to add namespace using system.data.sqlclient;
then connect to database by using this Base class library

step  2:if ur connecting with ur own system(PC) conect server as localhost
sqlconnection con =new sql connection("server=localhost;uid=sa;database=northwind");

step 3:if u want to connect as connection oriented we have to give
con.open();

step 4:then type a command
sqlcommand cmd =new sqlcommand (select * from products);

step 5:sqldatareader dr =cmd.executereader();
           while(dr.read())
           {
                         /*wat ever we want to execute we have to write in this loop
           }
dr.close();
con.close();

rahul.kale

  • Jan 22nd, 2008
 

1. Create Connection object
2. Open Connection
3. Create Command Object.
4. For insert,update,delete call ExecuteNonQuery() & For Select Create DataReader Object & Call ExecuteReader()
5. Close the Connection

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1. Implements the base class for data access
2. Create a connection
3. Open that connection
4. Create a data reader and execute the data reader with proper sql statements
 You can get the values of the record using the methods GetString, GetInt32 ....etc.

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TO Connect to a DatabaseFirst we need to have a namespace like System.Data.Sqlclientthen connect to database as follows1.Create connection using SqlConnection Sqlconnection con=new sqlconnection("Connectionstring")2.Open connection con.Open()3.Pass query using command object SqlCommand cmd=new sqlCommand("Sqlquery",con)4. Read the data using Datareader Datareader rd=cmd.ExecuteReader()5. Dispaly the data using display control6. Close the connection con.Close()

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