Retrieving Data Using a DataReader - ADO.NET (2023)

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To retrieve data using a DataReader, create an instance of the Command object, and then create a DataReader by calling Command.ExecuteReader to retrieve rows from a data source. The DataReader provides an unbuffered stream of data that allows procedural logic to efficiently process results from a data source sequentially. The DataReader is a good choice when you're retrieving large amounts of data because the data is not cached in memory.

The following example illustrates using a DataReader, where reader represents a valid DataReader and command represents a valid Command object.

reader = command.ExecuteReader(); 
reader = command.ExecuteReader()

Use the DataReader.Read method to obtain a row from the query results. You can access each column of the returned row by passing the name or ordinal number of the column to the DataReader. However, for best performance, the DataReader provides a series of methods that allow you to access column values in their native data types (GetDateTime, GetDouble, GetGuid, GetInt32, and so on). For a list of typed accessor methods for data provider-specific DataReaders, see OleDbDataReader and SqlDataReader. Using the typed accessor methods when you know the underlying data type reduces the amount of type conversion required when retrieving the column value.

(Video) Display Data Using DataReader Object in ASP.NET | ADO.NET

The following example iterates through a DataReader object and returns two columns from each row.

static void HasRows(SqlConnection connection){ using (connection) { SqlCommand command = new SqlCommand( "SELECT CategoryID, CategoryName FROM Categories;", connection); connection.Open(); SqlDataReader reader = command.ExecuteReader(); if (reader.HasRows) { while (reader.Read()) { Console.WriteLine("{0}\t{1}", reader.GetInt32(0), reader.GetString(1)); } } else { Console.WriteLine("No rows found."); } reader.Close(); }}
Private Sub HasRows(ByVal connection As SqlConnection) Using connection Dim command As SqlCommand = New SqlCommand( _ "SELECT CategoryID, CategoryName FROM Categories;", _ connection) connection.Open() Dim reader As SqlDataReader = command.ExecuteReader() If reader.HasRows Then Do While reader.Read() Console.WriteLine(reader.GetInt32(0) _ & vbTab & reader.GetString(1)) Loop Else Console.WriteLine("No rows found.") End If reader.Close() End UsingEnd Sub

Closing the DataReader

Always call the Close method when you have finished using the DataReader object.

If your Command contains output parameters or return values, those values are not available until the DataReader is closed.

While a DataReader is open, the Connection is in use exclusively by that DataReader. You cannot execute any commands for the Connection, including creating another DataReader, until the original DataReader is closed.

Note

Do not call Close or Dispose on a Connection, a DataReader, or any other managed object in the Finalize method of your class. In a finalizer, only release unmanaged resources that your class owns directly. If your class does not own any unmanaged resources, do not include a Finalize method in your class definition. For more information, see Garbage Collection.

(Video) Reading data with an SqlDataReader

Retrieving multiple result sets using NextResult

If the DataReader returns multiple result sets, call the NextResult method to iterate through the result sets sequentially. The following example shows the SqlDataReader processing the results of two SELECT statements using the ExecuteReader method.

static void RetrieveMultipleResults(SqlConnection connection){ using (connection) { SqlCommand command = new SqlCommand( "SELECT CategoryID, CategoryName FROM dbo.Categories;" + "SELECT EmployeeID, LastName FROM dbo.Employees", connection); connection.Open(); SqlDataReader reader = command.ExecuteReader(); while (reader.HasRows) { Console.WriteLine("\t{0}\t{1}", reader.GetName(0), reader.GetName(1)); while (reader.Read()) { Console.WriteLine("\t{0}\t{1}", reader.GetInt32(0), reader.GetString(1)); } reader.NextResult(); } }}
Private Sub RetrieveMultipleResults(ByVal connection As SqlConnection) Using connection Dim command As SqlCommand = New SqlCommand( _ "SELECT CategoryID, CategoryName FROM Categories;" & _ "SELECT EmployeeID, LastName FROM Employees", connection) connection.Open() Dim reader As SqlDataReader = command.ExecuteReader() Do While reader.HasRows Console.WriteLine(vbTab & reader.GetName(0) _ & vbTab & reader.GetName(1)) Do While reader.Read() Console.WriteLine(vbTab & reader.GetInt32(0) _ & vbTab & reader.GetString(1)) Loop reader.NextResult() Loop End UsingEnd Sub

Getting schema information from the DataReader

While a DataReader is open, you can retrieve schema information about the current result set using the GetSchemaTable method. GetSchemaTable returns a DataTable object populated with rows and columns that contain the schema information for the current result set. The DataTable contains one row for each column of the result set. Each column of the schema table maps to a property of the columns returned in the rows of the result set, where the ColumnName is the name of the property and the value of the column is the value of the property. The following example writes out the schema information for DataReader.

static void GetSchemaInfo(SqlConnection connection){ using (connection) { SqlCommand command = new SqlCommand( "SELECT CategoryID, CategoryName FROM Categories;", connection); connection.Open(); SqlDataReader reader = command.ExecuteReader(); DataTable schemaTable = reader.GetSchemaTable(); foreach (DataRow row in schemaTable.Rows) { foreach (DataColumn column in schemaTable.Columns) { Console.WriteLine(String.Format("{0} = {1}", column.ColumnName, row[column])); } } }}
Private Sub GetSchemaInfo(ByVal connection As SqlConnection) Using connection Dim command As SqlCommand = New SqlCommand( _ "SELECT CategoryID, CategoryName FROM Categories;", _ connection) connection.Open() Dim reader As SqlDataReader = command.ExecuteReader() Dim schemaTable As DataTable = reader.GetSchemaTable() Dim row As DataRow Dim column As DataColumn For Each row In schemaTable.Rows For Each column In schemaTable.Columns Console.WriteLine(String.Format("{0} = {1}", _ column.ColumnName, row(column))) Next Console.WriteLine() Next reader.Close() End UsingEnd Sub

Working with OLE DB chapters

Hierarchical rowsets, or chapters (OLE DB type DBTYPE_HCHAPTER, ADO type adChapter), can be retrieved using the OleDbDataReader. When a query that includes a chapter is returned as a DataReader, the chapter is returned as a column in that DataReader and is exposed as a DataReader object.

(Video) SqlDataReader in ADO.NET Part 8

The ADO.NET DataSet can also be used to represent hierarchical rowsets by using parent-child relationships between tables. For more information, see DataSets, DataTables, and DataViews.

The following code example uses the MSDataShape Provider to generate a chapter column of orders for each customer in a list of customers.

Using connection As OleDbConnection = New OleDbConnection( "Provider=MSDataShape;Data Provider=SQLOLEDB;" & "Data Source=localhost;Integrated Security=SSPI;Initial Catalog=northwind") Using custCMD As OleDbCommand = New OleDbCommand( "SHAPE {SELECT CustomerID, CompanyName FROM Customers} " & "APPEND ({SELECT CustomerID, OrderID FROM Orders} AS CustomerOrders " & "RELATE CustomerID TO CustomerID)", connection) connection.Open() Using custReader As OleDbDataReader = custCMD.ExecuteReader() Do While custReader.Read() Console.WriteLine("Orders for " & custReader.GetString(1)) ' custReader.GetString(1) = CompanyName Using orderReader As OleDbDataReader = custReader.GetValue(2) ' custReader.GetValue(2) = Orders chapter as DataReader Do While orderReader.Read() Console.WriteLine(vbTab & orderReader.GetInt32(1)) ' orderReader.GetInt32(1) = OrderID Loop orderReader.Close() End Using Loop ' Make sure to always close readers and connections. custReader.Close() End Using End UsingEnd Using
using (OleDbConnection connection = new OleDbConnection( "Provider=MSDataShape;Data Provider=SQLOLEDB;" + "Data Source=localhost;Integrated Security=SSPI;Initial Catalog=northwind")){ using (OleDbCommand custCMD = new OleDbCommand( "SHAPE {SELECT CustomerID, CompanyName FROM Customers} " + "APPEND ({SELECT CustomerID, OrderID FROM Orders} AS CustomerOrders " + "RELATE CustomerID TO CustomerID)", connection)) { connection.Open(); using (OleDbDataReader custReader = custCMD.ExecuteReader()) { while (custReader.Read()) { Console.WriteLine("Orders for " + custReader.GetString(1)); // custReader.GetString(1) = CompanyName using (OleDbDataReader orderReader = (OleDbDataReader)custReader.GetValue(2)) { // custReader.GetValue(2) = Orders chapter as DataReader while (orderReader.Read()) Console.WriteLine("\t" + orderReader.GetInt32(1)); // orderReader.GetInt32(1) = OrderID orderReader.Close(); } } // Make sure to always close readers and connections. custReader.Close(); } }}

Returning results with Oracle REF CURSORs

The .NET Framework Data Provider for Oracle supports the use of Oracle REF CURSORs to return a query result. An Oracle REF CURSOR is returned as an OracleDataReader.

You can retrieve an OracleDataReader object that represents an Oracle REF CURSOR by using the ExecuteReader method. You can also specify an OracleCommand that returns one or more Oracle REF CURSORs as the SelectCommand for an OracleDataAdapter used to fill a DataSet.

To access a REF CURSOR returned from an Oracle data source, create an OracleCommand for your query and add an output parameter that references the REF CURSOR to the Parameters collection of your OracleCommand. The name of the parameter must match the name of the REF CURSOR parameter in your query. Set the type of the parameter to OracleType.Cursor. The OracleCommand.ExecuteReader() method of your OracleCommand returns an OracleDataReader for the REF CURSOR.

(Video) How to Retrieve Data from Database using C# | retrieve data from sql server in c# | Ado.Net Tutorial

If your OracleCommand returns multiple REF CURSORS, add multiple output parameters. You can access the different REF CURSORs by calling the OracleCommand.ExecuteReader() method. The call to ExecuteReader() returns an OracleDataReader referencing the first REF CURSOR. You can then call the OracleDataReader.NextResult() method to access subsequent REF CURSORs. Although the parameters in your OracleCommand.Parameters collection match the REF CURSOR output parameters by name, the OracleDataReader accesses them in the order in which they were added to the Parameters collection.

For example, consider the following Oracle package and package body.

CREATE OR REPLACE PACKAGE CURSPKG AS TYPE T_CURSOR IS REF CURSOR; PROCEDURE OPEN_TWO_CURSORS (EMPCURSOR OUT T_CURSOR, DEPTCURSOR OUT T_CURSOR);END CURSPKG; CREATE OR REPLACE PACKAGE BODY CURSPKG AS PROCEDURE OPEN_TWO_CURSORS (EMPCURSOR OUT T_CURSOR, DEPTCURSOR OUT T_CURSOR) IS BEGIN OPEN EMPCURSOR FOR SELECT * FROM DEMO.EMPLOYEE; OPEN DEPTCURSOR FOR SELECT * FROM DEMO.DEPARTMENT; END OPEN_TWO_CURSORS;END CURSPKG;

The following code creates an OracleCommand that returns the REF CURSORs from the previous Oracle package by adding two parameters of type OracleType.Cursor to the OracleCommand.Parameters collection.

Dim cursCmd As OracleCommand = New OracleCommand("CURSPKG.OPEN_TWO_CURSORS", oraConn) cursCmd.Parameters.Add("EMPCURSOR", OracleType.Cursor).Direction = ParameterDirection.Output cursCmd.Parameters.Add("DEPTCURSOR", OracleType.Cursor).Direction = ParameterDirection.Output 
OracleCommand cursCmd = new OracleCommand("CURSPKG.OPEN_TWO_CURSORS", oraConn); cursCmd.Parameters.Add("EMPCURSOR", OracleType.Cursor).Direction = ParameterDirection.Output; cursCmd.Parameters.Add("DEPTCURSOR", OracleType.Cursor).Direction = ParameterDirection.Output; 

The following code returns the results of the previous command using the Read() and NextResult() methods of the OracleDataReader. The REF CURSOR parameters are returned in order.

oraConn.Open() Dim cursCmd As OracleCommand = New OracleCommand("CURSPKG.OPEN_TWO_CURSORS", oraConn) cursCmd.CommandType = CommandType.StoredProcedure cursCmd.Parameters.Add("EMPCURSOR", OracleType.Cursor).Direction = ParameterDirection.Output cursCmd.Parameters.Add("DEPTCURSOR", OracleType.Cursor).Direction = ParameterDirection.Output Dim reader As OracleDataReader = cursCmd.ExecuteReader() Console.WriteLine(vbCrLf & "Emp ID" & vbTab & "Name") Do While reader.Read() Console.WriteLine("{0}" & vbTab & "{1}, {2}", reader.GetOracleNumber(0), reader.GetString(1), reader.GetString(2)) Loop reader.NextResult() Console.WriteLine(vbCrLf & "Dept ID" & vbTab & "Name") Do While reader.Read() Console.WriteLine("{0}" & vbTab & "{1}", reader.GetOracleNumber(0), reader.GetString(1)) Loop ' Make sure to always close readers and connections. reader.Close() oraConn.Close() 
oraConn.Open(); OracleCommand cursCmd = new OracleCommand("CURSPKG.OPEN_TWO_CURSORS", oraConn); cursCmd.CommandType = CommandType.StoredProcedure; cursCmd.Parameters.Add("EMPCURSOR", OracleType.Cursor).Direction = ParameterDirection.Output; cursCmd.Parameters.Add("DEPTCURSOR", OracleType.Cursor).Direction = ParameterDirection.Output; OracleDataReader reader = cursCmd.ExecuteReader(); Console.WriteLine("\nEmp ID\tName"); while (reader.Read()) Console.WriteLine("{0}\t{1}, {2}", reader.GetOracleNumber(0), reader.GetString(1), reader.GetString(2)); reader.NextResult(); Console.WriteLine("\nDept ID\tName"); while (reader.Read()) Console.WriteLine("{0}\t{1}", reader.GetOracleNumber(0), reader.GetString(1)); // Make sure to always close readers and connections. reader.Close(); oraConn.Close(); 

The following example uses the previous command to populate a DataSet with the results of the Oracle package.

(Video) Retrieving multiple results sets using NextResult method of DataReader in C#

Dim ds As DataSet = New DataSet() Dim adapter As OracleDataAdapter = New OracleDataAdapter(cursCmd) adapter.TableMappings.Add("Table", "Employees") adapter.TableMappings.Add("Table1", "Departments") adapter.Fill(ds) 
DataSet ds = new DataSet(); OracleDataAdapter adapter = new OracleDataAdapter(cursCmd); adapter.TableMappings.Add("Table", "Employees"); adapter.TableMappings.Add("Table1", "Departments"); adapter.Fill(ds); 

Note

To avoid an OverflowException, we recommend that you also handle any conversion from the Oracle NUMBER type to a valid .NET Framework type before storing the value in a DataRow. You can use the FillError event to determine if an OverflowException has occurred. For more information on the FillError event, see Handling DataAdapter Events.

See also

  • DataAdapters and DataReaders
  • Commands and Parameters
  • Retrieving Database Schema Information
  • ADO.NET Overview

FAQs

Which object of ADO.NET has the best performance for retrieving the data DataSet DataReader data provider DataAdapter? ›

A DataReader object has faster access to data. A DataSet object has slower access to data.

How to retrieve data from database using DataReader in C#? ›

To retrieve data using a DataReader, create an instance of the Command object, and then create a DataReader by calling Command. ExecuteReader to retrieve rows from a data source.

What is DataReader in ADO.NET explain with example? ›

In ADO.NET, a DataReader is a broad category of objects used to sequentially read data from a data source. DataReaders provide a very efficient way to access data, and can be thought of as a Firehose cursor from ASP Classic, except that no server-side cursor is used.

Which ADO.NET method provides faster data retrieval? ›

ADO.NET works either in a connected or disconnected way. Connected mode is more popular as it has faster performance than disconnected mode because it works on the forward read-only method. The performance degradation in disconnected mode occurs due to multiple operations like insert, update, delete, and select data.

How many DataReader objects can be opened on a connection object at a time by default? ›

A Connection Object has only one DataReader at a time.

Is DataReader faster than DataSet? ›

DataReader provides faster performance, but has read-only and forward-only access. DataSet, on the other hand, is high resource-consuming, but offers more control and a disconnected nature.

How to get column value from DataReader in C#? ›

This method will populate our object array with the column values currently in the DataReader.
  1. ArrayList rowList = new ArrayList(); SqlDataReader reader = storedProcCommand.ExecuteReader(); while (reader.Read()) {
  2. object[] values = new object[reader.FieldCount];
  3. reader.GetValues(values);
  4. rowList.Add(values); }

Which method is used by DataReader? ›

Once the OleDbDataReader is initialize, you can utilize its various methods to read your data records. Foremost, you can use the Read method, which, when called repeatedly, continues to read each row of data into the DataReader object.

How do I check if a DataReader has a column? ›

string ColumnValue; if (dr["ColumnName"] != null) ColumnValue = dr["ColumnName"].

How to convert DataReader to DataTable in C#? ›

CommandTimeout = connectionTimeout; using (AdomdDataAdapter ad = new AdomdDataAdapter(cmd)) { DataTable dtData = new DataTable("Data"); DataTable dtSchema = new DataTable("Schema"); rdr = cmd. ExecuteReader(); if (rdr != null) { dtSchema = rdr.

How to retrieve data from database in C# using DataTable? ›

A new, empty DataTable is declared and instantiated. The Fill method from the SqlDataAdapter is then used to fill the DataTable with the data it retrieved from SQL Server. The last line refers to a DataGrid object on a Windows form. The DataGrid's DataSource property is set to the DataTable that we just filled.

How many number of records in memory at any given point of time when the DataReader reads the data? ›

What is a DataReader? A DataReader is a read-only stream of data returned from the database as the query executes. It only contains one row of data in memory at a time and is restricted to navigating forward only in the results one record at a time.

What is ADO explain with example? ›

(ActiveX Data Objects) A programming interface from Microsoft that is designed as "the" Microsoft standard for data access. First used with Internet Information Server, ADO is a set of COM objects that provides an interface to OLE DB. The three primary objects are Connection, Command and Recordset.

How does ADO.NET makes work so easy? ›

How does ADO.NET Makes Work so Easy? ADO.NET follows sets of instructions using which we can establish connectivity between back-end technology and database.

How can I speed up my data retrieval? ›

Tips to Increase Database Performance
  1. Tip 1: Optimize Queries. ...
  2. Tip 2: Improve Indexes. ...
  3. Tip 3: Defragment Data. ...
  4. Tip 4: Increase Memory. ...
  5. Tip 5: Strengthen CPU. ...
  6. Tip 6: Review Access. ...
  7. SolarWinds Database Performance Analyzer (DPA) ...
  8. SolarWinds Database Performance Monitor (DPM)
May 10, 2021

Which is used to improve the speed of data retrieval operations? ›

Indexing. One way to improve the speed at which transactions are retrieved from a database is to create and use indexes. You can implement indexes on the database side where the queries are executed.

Which statement is not true about DataReader object? ›

Datareader fetches a value in backword only mode option is wrong because it fetches value in FORWARD-ONLY mode.

How many number of rows will be retrieved through DataReader at a time in ADO.NET application? ›

By default DataReader stores only one row at a time in memory.

Which is the correct option about DataReader? ›

3. Choose the correct option about DataReader object. A) DataReader object is a forward-only object.

When we can use a DataSet over a DataReader based on the scenarios? ›

Finally, one of the more compelling reasons to use a DataSet instead of a DataReader is that the DataSet can be serialized when the rowset needs to be passed around a network or the Internet. A DataReader cannot be serialized to XML due to its connected nature.

Does DataReader use more memory? ›

The DataReader object is fast, returning a fire hose of read-only data from the server, one record at a time. In addition, retrieving results with a DataReader requires significantly less memory than creating a DataSet.

Which is better DataReader or DataAdapter? ›

Using a DataReader produces faster results than using a DataAdapter to return the same data. Because the DataAdapter actually uses a DataReader to retrieve data, this should not surprise us. But there are many other reasons as well. DataReaders provide multiple asynchronous methods that can be employed.

Can DataReader have multiple tables? ›

Answer: Data reader can hold data from multiple tables and datareader can hold more than one table.

How to convert DataReader to list in C#? ›

The following is the code for converting the DataReader to a List. The following is the code for converting the DataSet to a List.
...
xaml View design part use the following code:
  1. <Window x:Class="DataReaderToList. ...
  2. Title="EmployeeList" Height="350" Width="525">
  3. <Grid>
  4. <Grid. ...
  5. <RowDefinition Height="*"/>
  6. </Grid.
Nov 8, 2014

How to open SqlDataReader in C#? ›

In order to create the instance of SqlDataReader class, what you need to do is, call the ExecuteReader method of the SqlCommand object which will return an instance of SqlDataReader class as shown in the below image.

How to use ExecuteReader in C# with stored procedure? ›

ExecuteReader only returns rows where Country = "UK". To return a value from a stored procedure, the only thing you need to do is change the stored procedure, which will store and return a value as a parameter, and set the parameter's Direction property as follows: SqlParameter param = new SqlParameter();

Which method is used for read operation? ›

A - Readable stream is used for read operation. B - Output of readable stream can be input to a writable stream.

What is difference between DataTable and DataReader? ›

DataReader requires an open connection in order to execute the SQL statement. Example would be fetching Name City for all records in the Person Table using DataReader. DataAdapter is used to execute SQL statements and is used to populate the results of SQL Query into a DataSet or DataTable.

Which of the following is not DataReader method? ›

Experiment is not a method of data collection.

How does DataReader work in C#? ›

Introduction to DataReader C# A Data reader is an object that is used to read data from the data sources. This can only perform read operation and not update operation on the data source. The data is retrieved as a data stream from the data source.

Why is column read only? ›

This happens when the source table has an identity column which is auto-generated at source and also at the destination. Since it's auto-generated by system, import/export can't overwrite identity data and treats it as read-only column.

Which method can be used to get the name of the column in a DataReader? ›

There is a GetName function on the SqlDataReader which accepts the column index and returns the name of the column. Conversely, there is a GetOrdinal which takes in a column name and returns the column index.

How to load DataReader into DataTable? ›

Load() and the second one, by manually converting a DataReader to a DataTable.
  1. Step 1: Create a new ASP.NET application. ...
  2. Step 2: Let us first see how to convert a DataReader to a DataTable using the easy way out. ...
  3. Step 3: The method shown in the Step 2 was the easy way out. ...
  4. Step 4: Call the two methods on the PageLoad()
Apr 18, 2008

How do you execute multiple SQL statements using DataReader? ›

To execute more than one SQL statement, set the CommandText property of a Command object to multiple SQL statements separated by semicolons (;). After calling the ExecuteReader method, the DataReader will hold the number of result sets equal to the number of SQL statements executed.

What is the difference between DataSet and DataTable? ›

A DataSet is made up of a collection of tables, relationships, and constraints. In ADO.NET, DataTable objects are used to represent the tables in a DataSet. A DataTable represents one table of in-memory relational data; the data is local to the .

How to get all data from database in C#? ›

Write code to retrieve data from SQL database in C# asp net
  1. Create an object of SqlConnection class.
  2. Prepare connection string for SqlConnection class object.
  3. Create object of SqlCommand class and prepare sql command with types, queries and sql connection object.
  4. Open sql connection.
  5. Execute sql query with cmd.
Dec 29, 2016

How can we get data from table in Ado net? ›

Reading Data (ADO.Net)
  1. Create a connection to the database.
  2. Create a command object using the connection. VerticaCommand command = _conn. ...
  3. Create a query. ...
  4. Execute the reader to return the results from the query. ...
  5. Read the data. ...
  6. When you're finished, close the data reader to free up resources.

How to retrieve data from database using SELECT query in C#? ›

Introduction
  1. Open Visual Studio and create a new Windows form application.
  2. Create a form using buttons (insert ,search,update,delete and navigation), textbox, labels, and datagridview.
  3. After creating the form, connect the database to the form. For that right click on the form and it opens Form1. cs.
Jun 1, 2022

Why DataReader is faster than DataSet? ›

DataReader is a stream which is readonly and forward only. It fetches the record from databse and stores in the network buffer and gives whenever requests. DataReader releasese the records as query executes and do not wait for the entire query to execute. Therefore it is very fast as compare to the dataset.

Which object of ADO.NET has best performance for retrieving the data? ›

A DataReader object has faster access to data. A DataSet object has slower access to data.

What is ADO.NET simple words? ›

ADO.NET is a data access technology from the Microsoft . NET Framework that provides communication between relational and non-relational systems through a common set of components. ADO.NET is a set of computer software components that programmers can use to access data and data services from a database.

What is ADO.NET and why it is used? ›

ADO.NET provides consistent access to data sources such as SQL Server and XML, and to data sources exposed through OLE DB and ODBC. Data-sharing consumer applications can use ADO.NET to connect to these data sources and retrieve, handle, and update the data that they contain.

What is ADO.NET interview questions? ›

ADO.NET Interview Questions for Freshers
  • What is ADO.NET? ...
  • What is DataSet in ADO.NET? ...
  • Give the differences between ADO and ADO.NET. ...
  • What is a DataAdapter in ADO.NET? ...
  • Explain the difference between ADO.NET and ASP.NET. ...
  • Explain about DataSet types in ADO.NET. ...
  • Explain the difference between DataTable and DataSet.
Dec 19, 2022

What is the limitation of ADO? ›

ADO applications have limitations with calling stored procedures, inserting a new row by using a server-side scrollable cursor, and no support for default parameter values. The limitations for ADO applications are: ADO applications calling stored procedures must have their parameters created and explicitly bound.

Is ADO.NET obsolete? ›

It isn't obsolete, it is the foundation for working with databases in . NET.

Is ADO faster than ODBC? ›

There is no speed advantage inherent to ODBC vs ADO.NET, but there is some speed loss for such bridged solutions, due to the extra layer of API translation.

Which ADO.NET object is very fast in getting data from the database? ›

10) Which ADO.NET object is very fast in getting data from the database? SqlDataReader object.

What ADO.NET object provides a high performance stream of data from the data source? ›

The DataReader provides a high-performance stream of data from the data source. Finally, the DataAdapter provides the bridge between the DataSet object and the data source.

What ADO object is used to process records retrieved from a database table? ›

The ADO Recordset object is used to hold a set of records from a database table. A Recordset object consist of records and columns (fields). In ADO, this object is the most important and the one used most often to manipulate data from a database.

Which of the following object is used by the DataAdapter to retrieve the data from database? ›

The DataAdapter uses the Connection object of the . NET Framework data provider to connect to a data source, and it uses Command objects to retrieve data from and resolve changes to the data source.

Which command is mostly used to retrieve data? ›

SQL is the Structured Query Language used to store, manipulate, and retrieve data present in a database server.

How does ADO.NET perform database operations? ›

It uses a connection object to perform these actions on the database. A Connection object specifies the type of interaction to perform with the database, like SELECT, INSERT, UPDATE, or DELETE. A Command object is used to perform various types of operations, like SELECT, INSERT, UPDATE, or DELETE on the database.

Which ADO.NET object acts as a bridge between DataSet and database? ›

DataAdapter Class

A DataAdapter object is used as a bridge between a database and a DataSet.

Which ADO.NET component is used to fill DataTable *? ›

Command Class

ExecuteReader: Returns data to the client as rows. This would typically be an SQL select statement or a Stored Procedure that contains one or more select statements. This method returns a DataReader object that can be used to fill a DataTable object or used directly for printing reports and so forth.

Which method would you call to retrieve data using Command object? ›

ExecuteScalar Method
  1. The ExecuteScalar Method in SqlCommandObject returns the first column of the first row after executing the query against the Data Source.
  2. If the result set contains more than one column or rows, it takes only the first column of the first row. ...
  3. If the result set is empty it will return null.
Jul 9, 2019

What is to retrieve records from the table? ›

In SQL, to retrieve data stored in our tables, we use the SELECT statement. The result of this statement is always in the form of a table that we can view with our database client software or use with programming languages to build dynamic web pages or desktop applications.

Which is used to retrieve specific data from the table? ›

The SELECT statement is used to pull information from a table.

What is DataAdapter and DataReader in ADO net? ›

Using the DataReader can increase application performance both by retrieving data as soon as it is available, and (by default) storing only one row at a time in memory, reducing system overhead. A DataAdapter is used to retrieve data from a data source and populate tables within a DataSet.

How do I access my data on ADO net? ›

The basic flow to accessing a data object is to: Create a connection to the data object. Create a command for the data object to act upon.
...
In order to accomplish the above steps we will need to use the following classes:
  1. Data. SqlClient. SqlConnection.
  2. Data. SqlClient. SqlCommand.
  3. Data. SqlClient. SqlDataReader.
Sep 30, 2012

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Name: Edwin Metz

Birthday: 1997-04-16

Address: 51593 Leanne Light, Kuphalmouth, DE 50012-5183

Phone: +639107620957

Job: Corporate Banking Technician

Hobby: Reading, scrapbook, role-playing games, Fishing, Fishing, Scuba diving, Beekeeping

Introduction: My name is Edwin Metz, I am a fair, energetic, helpful, brave, outstanding, nice, helpful person who loves writing and wants to share my knowledge and understanding with you.