SqlDataReader Class

SqlDataReader Class

 

Provides a way of reading a forward-only stream of rows from a SQL Server database. This class cannot be inherited.

Namespace:   System.Data.SqlClient
Assembly:  System.Data (in System.Data.dll)

System.Object
  System.MarshalByRefObject
    System.Data.Common.DbDataReader
      System.Data.SqlClient.SqlDataReader

public class SqlDataReader : DbDataReader, IDataReader, IDisposable, 
	IDataRecord

NameDescription
System_CAPS_protpropertyConnection

Gets the SqlConnection associated with the SqlDataReader.

System_CAPS_pubpropertyDepth

Gets a value that indicates the depth of nesting for the current row.(Overrides DbDataReader.Depth.)

System_CAPS_pubpropertyFieldCount

Gets the number of columns in the current row.(Overrides DbDataReader.FieldCount.)

System_CAPS_pubpropertyHasRows

Gets a value that indicates whether the SqlDataReader contains one or more rows.(Overrides DbDataReader.HasRows.)

System_CAPS_pubpropertyIsClosed

Retrieves a Boolean value that indicates whether the specified SqlDataReader instance has been closed. (Overrides DbDataReader.IsClosed.)

System_CAPS_pubpropertyItem[Int32]

Gets the value of the specified column in its native format given the column ordinal.(Overrides DbDataReader.Item[Int32].)

System_CAPS_pubpropertyItem[String]

Gets the value of the specified column in its native format given the column name.(Overrides DbDataReader.Item[String].)

System_CAPS_pubpropertyRecordsAffected

Gets the number of rows changed, inserted, or deleted by execution of the Transact-SQL statement.(Overrides DbDataReader.RecordsAffected.)

System_CAPS_pubpropertyVisibleFieldCount

Gets the number of fields in the SqlDataReader that are not hidden. (Overrides DbDataReader.VisibleFieldCount.)

NameDescription
System_CAPS_pubmethodClose()

Closes the SqlDataReader object.(Overrides DbDataReader.Close().)

System_CAPS_pubmethodCreateObjRef(Type)

Creates an object that contains all the relevant information required to generate a proxy used to communicate with a remote object.(Inherited from MarshalByRefObject.)

System_CAPS_pubmethodDispose()

Releases all resources used by the current instance of the DbDataReader class.(Inherited from DbDataReader.)

System_CAPS_protmethodDispose(Boolean)

Releases the managed resources used by the DbDataReader and optionally releases the unmanaged resources.(Inherited from DbDataReader.)

System_CAPS_pubmethodEquals(Object)

Determines whether the specified object is equal to the current object.(Inherited from Object.)

System_CAPS_protmethodFinalize()

Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection.(Inherited from Object.)

System_CAPS_pubmethodGetBoolean(Int32)

Gets the value of the specified column as a Boolean.(Overrides DbDataReader.GetBoolean(Int32).)

System_CAPS_pubmethodGetByte(Int32)

Gets the value of the specified column as a byte.(Overrides DbDataReader.GetByte(Int32).)

System_CAPS_pubmethodGetBytes(Int32, Int64, Byte[], Int32, Int32)

Reads a stream of bytes from the specified column offset into the buffer an array starting at the given buffer offset.(Overrides DbDataReader.GetBytes(Int32, Int64, Byte[], Int32, Int32).)

System_CAPS_pubmethodGetChar(Int32)

Gets the value of the specified column as a single character.(Overrides DbDataReader.GetChar(Int32).)

System_CAPS_pubmethodGetChars(Int32, Int64, Char[], Int32, Int32)

Reads a stream of characters from the specified column offset into the buffer as an array starting at the given buffer offset.(Overrides DbDataReader.GetChars(Int32, Int64, Char[], Int32, Int32).)

System_CAPS_pubmethodGetData(Int32)

Returns a DbDataReader object for the requested column ordinal.(Inherited from DbDataReader.)

System_CAPS_pubmethodGetDataTypeName(Int32)

Gets a string representing the data type of the specified column.(Overrides DbDataReader.GetDataTypeName(Int32).)

System_CAPS_pubmethodGetDateTime(Int32)

Gets the value of the specified column as a DateTime object.(Overrides DbDataReader.GetDateTime(Int32).)

System_CAPS_pubmethodGetDateTimeOffset(Int32)

Retrieves the value of the specified column as a DateTimeOffset object.

System_CAPS_protmethodGetDbDataReader(Int32)

Returns a DbDataReader object for the requested column ordinal that can be overridden with a provider-specific implementation.(Inherited from DbDataReader.)

System_CAPS_pubmethodGetDecimal(Int32)

Gets the value of the specified column as a Decimal object.(Overrides DbDataReader.GetDecimal(Int32).)

System_CAPS_pubmethodGetDouble(Int32)

Gets the value of the specified column as a double-precision floating point number.(Overrides DbDataReader.GetDouble(Int32).)

System_CAPS_pubmethodGetEnumerator()

Returns an IEnumerator that iterates through the SqlDataReader.(Overrides DbDataReader.GetEnumerator().)

System_CAPS_pubmethodGetFieldType(Int32)

Gets the Type that is the data type of the object.(Overrides DbDataReader.GetFieldType(Int32).)

System_CAPS_pubmethodGetFieldValue<T>(Int32)

Synchronously gets the value of the specified column as a type. GetFieldValueAsync<T> is the asynchronous version of this method.(Overrides DbDataReader.GetFieldValue<T>(Int32).)

System_CAPS_pubmethodGetFieldValueAsync<T>(Int32)

Asynchronously gets the value of the specified column as a type.(Inherited from DbDataReader.)

System_CAPS_pubmethodGetFieldValueAsync<T>(Int32, CancellationToken)

Asynchronously gets the value of the specified column as a type. GetFieldValue<T> is the synchronous version of this method.(Overrides DbDataReader.GetFieldValueAsync<T>(Int32, CancellationToken).)

System_CAPS_pubmethodGetFloat(Int32)

Gets the value of the specified column as a single-precision floating point number.(Overrides DbDataReader.GetFloat(Int32).)

System_CAPS_pubmethodGetGuid(Int32)

Gets the value of the specified column as a globally unique identifier (GUID).(Overrides DbDataReader.GetGuid(Int32).)

System_CAPS_pubmethodGetHashCode()

Serves as the default hash function. (Inherited from Object.)

System_CAPS_pubmethodGetInt16(Int32)

Gets the value of the specified column as a 16-bit signed integer.(Overrides DbDataReader.GetInt16(Int32).)

System_CAPS_pubmethodGetInt32(Int32)

Gets the value of the specified column as a 32-bit signed integer.(Overrides DbDataReader.GetInt32(Int32).)

System_CAPS_pubmethodGetInt64(Int32)

Gets the value of the specified column as a 64-bit signed integer.(Overrides DbDataReader.GetInt64(Int32).)

System_CAPS_pubmethodGetLifetimeService()

Retrieves the current lifetime service object that controls the lifetime policy for this instance.(Inherited from MarshalByRefObject.)

System_CAPS_pubmethodGetName(Int32)

Gets the name of the specified column.(Overrides DbDataReader.GetName(Int32).)

System_CAPS_pubmethodGetOrdinal(String)

Gets the column ordinal, given the name of the column.(Overrides DbDataReader.GetOrdinal(String).)

System_CAPS_pubmethodGetProviderSpecificFieldType(Int32)

Gets an Object that is a representation of the underlying provider-specific field type.(Overrides DbDataReader.GetProviderSpecificFieldType(Int32).)

System_CAPS_pubmethodGetProviderSpecificValue(Int32)

Gets an Object that is a representation of the underlying provider specific value.(Overrides DbDataReader.GetProviderSpecificValue(Int32).)

System_CAPS_pubmethodGetProviderSpecificValues(Object[])

Gets an array of objects that are a representation of the underlying provider specific values.(Overrides DbDataReader.GetProviderSpecificValues(Object[]).)

System_CAPS_pubmethodGetSchemaTable()

Returns a DataTable that describes the column metadata of the SqlDataReader.(Overrides DbDataReader.GetSchemaTable().)

System_CAPS_pubmethodGetSqlBinary(Int32)

Gets the value of the specified column as a SqlBinary.

System_CAPS_pubmethodGetSqlBoolean(Int32)

Gets the value of the specified column as a SqlBoolean.

System_CAPS_pubmethodGetSqlByte(Int32)

Gets the value of the specified column as a SqlByte.

System_CAPS_pubmethodGetSqlBytes(Int32)

Gets the value of the specified column as SqlBytes.

System_CAPS_pubmethodGetSqlChars(Int32)

Gets the value of the specified column as SqlChars.

System_CAPS_pubmethodGetSqlDateTime(Int32)

Gets the value of the specified column as a SqlDateTime.

System_CAPS_pubmethodGetSqlDecimal(Int32)

Gets the value of the specified column as a SqlDecimal.

System_CAPS_pubmethodGetSqlDouble(Int32)

Gets the value of the specified column as a SqlDouble.

System_CAPS_pubmethodGetSqlGuid(Int32)

Gets the value of the specified column as a SqlGuid.

System_CAPS_pubmethodGetSqlInt16(Int32)

Gets the value of the specified column as a SqlInt16.

System_CAPS_pubmethodGetSqlInt32(Int32)

Gets the value of the specified column as a SqlInt32.

System_CAPS_pubmethodGetSqlInt64(Int32)

Gets the value of the specified column as a SqlInt64.

System_CAPS_pubmethodGetSqlMoney(Int32)

Gets the value of the specified column as a SqlMoney.

System_CAPS_pubmethodGetSqlSingle(Int32)

Gets the value of the specified column as a SqlSingle.

System_CAPS_pubmethodGetSqlString(Int32)

Gets the value of the specified column as a SqlString.

System_CAPS_pubmethodGetSqlValue(Int32)

Returns the data value in the specified column as a SQL Server type.

System_CAPS_pubmethodGetSqlValues(Object[])

Fills an array of Object that contains the values for all the columns in the record, expressed as SQL Server types.

System_CAPS_pubmethodGetSqlXml(Int32)

Gets the value of the specified column as an XML value.

System_CAPS_pubmethodGetStream(Int32)

Retrieves binary, image, varbinary, UDT, and variant data types as a Stream.(Overrides DbDataReader.GetStream(Int32).)

System_CAPS_pubmethodGetString(Int32)

Gets the value of the specified column as a string.(Overrides DbDataReader.GetString(Int32).)

System_CAPS_pubmethodGetTextReader(Int32)

Retrieves Char, NChar, NText, NVarChar, text, varChar, and Variant data types as a TextReader.(Overrides DbDataReader.GetTextReader(Int32).)

System_CAPS_pubmethodGetTimeSpan(Int32)

Retrieves the value of the specified column as a TimeSpan object.

System_CAPS_pubmethodGetType()

Gets the Type of the current instance.(Inherited from Object.)

System_CAPS_pubmethodGetValue(Int32)

Gets the value of the specified column in its native format.(Overrides DbDataReader.GetValue(Int32).)

System_CAPS_pubmethodGetValues(Object[])

Populates an array of objects with the column values of the current row.(Overrides DbDataReader.GetValues(Object[]).)

System_CAPS_pubmethodGetXmlReader(Int32)

Retrieves data of type XML as an XmlReader.

System_CAPS_pubmethodInitializeLifetimeService()

Obtains a lifetime service object to control the lifetime policy for this instance.(Inherited from MarshalByRefObject.)

System_CAPS_protmethodIsCommandBehavior(CommandBehavior)

Determines whether the specified CommandBehavior matches that of the SqlDataReader .

System_CAPS_pubmethodIsDBNull(Int32)

Gets a value that indicates whether the column contains non-existent or missing values.(Overrides DbDataReader.IsDBNull(Int32).)

System_CAPS_pubmethodIsDBNullAsync(Int32)

An asynchronous version of IsDBNull, which gets a value that indicates whether the column contains non-existent or missing values.(Inherited from DbDataReader.)

System_CAPS_pubmethodIsDBNullAsync(Int32, CancellationToken)

An asynchronous version of IsDBNull, which gets a value that indicates whether the column contains non-existent or missing values.

The cancellation token can be used to request that the operation be abandoned before the command timeout elapses. Exceptions will be reported via the returned Task object.(Overrides DbDataReader.IsDBNullAsync(Int32, CancellationToken).)

System_CAPS_protmethodMemberwiseClone()

Creates a shallow copy of the current Object.(Inherited from Object.)

System_CAPS_protmethodMemberwiseClone(Boolean)

Creates a shallow copy of the current MarshalByRefObject object.(Inherited from MarshalByRefObject.)

System_CAPS_pubmethodNextResult()

Advances the data reader to the next result, when reading the results of batch Transact-SQL statements.(Overrides DbDataReader.NextResult().)

System_CAPS_pubmethodNextResultAsync()

An asynchronous version of NextResult, which advances the reader to the next result when reading the results of a batch of statements.

Invokes NextResultAsync with CancellationToken.None.(Inherited from DbDataReader.)

System_CAPS_pubmethodNextResultAsync(CancellationToken)

An asynchronous version of NextResult, which advances the data reader to the next result, when reading the results of batch Transact-SQL statements.

The cancellation token can be used to request that the operation be abandoned before the command timeout elapses. Exceptions will be reported via the returned Task object.(Overrides DbDataReader.NextResultAsync(CancellationToken).)

System_CAPS_pubmethodRead()

Advances the SqlDataReader to the next record.(Overrides DbDataReader.Read().)

System_CAPS_pubmethodReadAsync()

An asynchronous version of Read, which advances the reader to the next record in a result set. This method invokes ReadAsync with CancellationToken.None.(Inherited from DbDataReader.)

System_CAPS_pubmethodReadAsync(CancellationToken)

An asynchronous version of Read, which advances the SqlDataReader to the next record.

The cancellation token can be used to request that the operation be abandoned before the command timeout elapses. Exceptions will be reported via the returned Task object.(Overrides DbDataReader.ReadAsync(CancellationToken).)

System_CAPS_pubmethodToString()

Returns a string that represents the current object.(Inherited from Object.)

NameDescription
System_CAPS_pubinterfaceSystem_CAPS_privmethodIDataRecord.GetData(Int32)

Returns an IDataReader for the specified column ordinal.

NameDescription
System_CAPS_pubmethodAsParallel()

Overloaded. Enables parallelization of a query.(Defined by ParallelEnumerable.)

System_CAPS_pubmethodAsQueryable()

Overloaded. Converts an IEnumerable to an IQueryable.(Defined by Queryable.)

System_CAPS_pubmethodCast<TResult>()

Casts the elements of an IEnumerable to the specified type.(Defined by Enumerable.)

System_CAPS_pubmethodOfType<TResult>()

Filters the elements of an IEnumerable based on a specified type.(Defined by Enumerable.)

To create a SqlDataReader, you must call the ExecuteReader method of the SqlCommand object, instead of directly using a constructor.

While the SqlDataReader is being used, the associated SqlConnection is busy serving the SqlDataReader, and no other operations can be performed on the SqlConnection other than closing it. This is the case until the Close method of the SqlDataReader is called. For example, you cannot retrieve output parameters until after you call Close.

Changes made to a result set by another process or thread while data is being read may be visible to the user of the SqlDataReader. However, the precise behavior is timing dependent.

IsClosed and RecordsAffected are the only properties that you can call after the SqlDataReader is closed. Although the RecordsAffected property may be accessed while the SqlDataReader exists, always call Close before returning the value of RecordsAffected to guarantee an accurate return value.

When using sequential access (CommandBehavior.SequentialAccess), an InvalidOperationException will be raised if the SqlDataReader position is advanced and another read operation is attempted on the previous column.

System_CAPS_noteNote

For optimal performance, SqlDataReader avoids creating unnecessary objects or making unnecessary copies of data. Therefore, multiple calls to methods such as GetValue return a reference to the same object. Use caution if you are modifying the underlying value of the objects returned by methods such as GetValue.

The following example creates a SqlConnection, a SqlCommand, and a SqlDataReader. The example reads through the data, writing it out to the console window. The code then closes the SqlDataReader. The SqlConnection is closed automatically at the end of the using code block.

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


class Program
{
    static void Main()
    {
        string str = "Data Source=(local);Initial Catalog=Northwind;"
            + "Integrated Security=SSPI";
        ReadOrderData(str);
    }

    private static void ReadOrderData(string connectionString)
    {
        string queryString =
            "SELECT OrderID, CustomerID FROM dbo.Orders;";

        using (SqlConnection connection =
                   new SqlConnection(connectionString))
        {
            SqlCommand command =
                new SqlCommand(queryString, connection);
            connection.Open();

            SqlDataReader reader = command.ExecuteReader();

            // Call Read before accessing data.
            while (reader.Read())
            {
                ReadSingleRow((IDataRecord)reader);
            }

            // Call Close when done reading.
            reader.Close();
        }
    }

    private static void ReadSingleRow(IDataRecord record)
    {
        Console.WriteLine(String.Format("{0}, {1}", record[0], record[1]));
    }

}

.NET Framework
Available since 1.1

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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