1)How to Convert DataSet to DataReader ?
ADO.NET table content a method CreateDataReader , you can convert a table to a DataReader.
DataTableReader dr=ds.Table[1].CreateDataReader();
Example
namespace
ConsoleApplication1
{
class
Program
{
static
void
Main(string[]
args)
{
DataSet
ds = new
DataSet();
DataTable
dt = new
DataTable();
dt.Columns.Add("Name");
DataRow
nr1 = dt.NewRow();
nr1["Name"]
= "John1";
dt.Rows.Add(nr1);
DataRow
nr2 = dt.NewRow();
nr2["Name"]
= "John2";
dt.Rows.Add(nr2);
ds.Tables.Add(dt);
DataTableReader
dr = ds.Tables[0].CreateDataReader();
while
(dr.Read())
{
Console.WriteLine("Name="
+ dr[0].ToString());
}
dr.Close();
Console.ReadKey();
}
}
}
Output :
Name=John1
Name=John2
Name=John2
2)Which is fast , DataReader or DataSet ?
DataReader is fast in compared to the DataSet. Internally Dataset use DataReader to retrieve the data.
3)What is DAO ?
DAO stands for data access object. Data access Technology from Microsoft to access database like Microsoft Access etc. It was introduced in Microsoft Visual Basic. It was connection oriented and need an active connection till the end.DAO is capable to handle local and remote database and also capable to perform insert ,update, delete operation.
4)What is maximum pool size of a connection pool ?
The maximum connection pool size is 100 by default. If you try to open connection more than pool size, connection Timeout error will be Occur.
5)What are the namespace used in ADO.NET ?
System.Data : This namespace provide the basic classes for data access and manipulation. For example DataSet, datatable, DataView comes under this lenses.
System.Data.Common : This namespace also provide some basic functionality related to the data access and manipulation. DataAdaptor, dbconnection classes comes under this namespace.
System.Data.Oledb : This namespace provide the classes for accessing Microsoft Access, Microsoft Excel, Oracle etc. This namespace provide classes for OLEDB connection,OLEDB command etc.
System.Data.SQLclient : This namespace provide the classes for accessing data Microsoft SQL server 7.0 and upper version. Namespace provides classes for SQL connection,SQL commands etc.
System.Data.Sqltype : This name space provide classes , that are quite similar to the .Net Framework variables, but quite familiar to SQL server. These classes are alternative to the .Net Framework variables, but more faster and safer. For example SqlBytes ,SqlChar,SqlFilestream etc.
6)What is Databinding ?
Databinding is a method to bind a data source with a control. The control will be populate, with the data from data source. For example, bind gridview with datatable, gridview rows and columns will be automatically populated. You do not need to add rows and columns programmatically. If you bind dropdownlist with a data source, the dropdownlist will be populated automatically no need to add item in it.Most of the asp.Net control support databinding.
7)Which is the object, get data from data source fast and quick ?
DataReader is a component of.Net framework, which fetch data from data source fast and quick. Another technique is DataSet set to fetch data using DataAdapter. DataSet internally use data reader to fetch data . Data reader is a component to fetch data from a database, it is the fastest.
7)What is ExecuteScalar ?
A command is executed against a connection. Command maybe store procedure or a SQL query. After execution command , a complete set of data or single value on all can be return. When it is expected that is single value will be returned , ExecuteScalar is used. If more than one value is return, say it the Datatable is returned, the first row and the first column of the Datatable will be considered, rest will be discarded. If null value is returned, it will throw an error.ExecuteScalar suitable for agree gate for calculating function like sum,multiply,average etc.
8)What is ExecuteNonQuery ?
A command is fire against a connection .The command may contain SQL statement of stored procedures . ExecuteNonQuery is used, it is expected that no results it will be returned after the command execution. It is most commonly used and very popular execution type.ExecuteNonQuery returns number of rows affected by the query.
9)What is DataSet copy method ?
DataSet copy method , make a exact copy of a database from another database.
DataSet
ds1 = new
DataSet();
DataSet
ds2;
ds2
= ds.Copy();
copy is done bye copying rows and columns and corresponding data, data relation, table relation and schema from the source database to the database. It is actually clone of a source database.
10) What is DataSet, haschanged method ?
A DataSet have multiple table , rows and columns. It is very difficult to detect any change is made in rows column of data.
DataSet.Haschanged() method help ask to detect any change have been made in the DataSet or not.
DataSet
ds = new
DataSet();
if
(ds.HasChanges())
{
return;
}
This method return and indicating value if there is any change made in the DataSet after it has been last loaded.
11) What is disconnected data in ADO.Net ?
ADO.NET use DataSet , DataAdopter , Connection string to retrieve data from database.DataAdopter takes connection information, SQL statement and create a channel in encrypted format to retrieve data from database.This data is filled to DataSet. DataSet hold multiple tables , rows columns and corresponding data ,DataSet also holds relationship schema of the respective tables and data. This is called disconnected data, a copy of data in the DataSet with SQL schema is considered as disconnected data.
13)What are the various method to generate and read XML ?
a)ReadXML()
b)GetXML()
c)WriteXML()
14)What is the use of System.Xml namespace ?
This namespace provide the classes for read ,write, delete XML.System. XmlNode ,XmlAttribute and many class to manipulate and details operation of XML file is managed .
