ULDataReader class

Represents a read-only bi-directional cursor in an UltraLite database.

Visual Basic syntax

Public Class ULDataReader
    Inherits System.Data.Common.DbDataReader
    Implements System.ComponentModel.IListSource

C# syntax

public class ULDataReader : 
    System.Data.Common.DbDataReader, 
    System.ComponentModel.IListSource

Members

All members of the ULDataReader class, including all inherited members.

Name	Description
Close method	Closes the cursor.
Dispose method (Inherited from System.Data.Common.DbDataReader)	Releases all resources used by the current instance of the System.Data.Common.DbDataReader class.
GetBoolean method	Returns the value for the specified column as a System.Boolean.
GetByte method	Returns the value for the specified column as an unsigned 8-bit value (System.Byte).
GetBytes method	UL Ext: Returns the value for the specified column as an array of System.Bytes values.
GetChar method	This method is not supported in UltraLite.NET.
GetChars method	Copies a subset of the value for the specified ULDbType.LongVarchar column, beginning at the specified offset, to the specified offset of the destination System.Char array.
GetData method (Inherited from System.Data.Common.DbDataReader)	Returns a System.Data.Common.DbDataReader object for the requested column ordinal.
GetDataTypeName method	Returns the name of the specified column's provider data type.
GetDateTime method	Returns the value for the specified column as a System.DateTime type with millisecond accuracy.
GetDbDataReader method (Inherited from System.Data.Common.DbDataReader)	Returns a System.Data.Common.DbDataReader object for the requested column ordinal that can be overridden with a provider-specific implementation.
GetDecimal method	Returns the value for the specified column as a System.Decimal type.
GetDouble method	Returns the value for the specified column as a System.Double type.
GetEnumerator method	Returns an System.Collections.IEnumerator value that iterates through the ULDataReader object.
GetFieldType method	Returns the System.Type value most appropriate for the specified column.
GetFieldValue(T) method (Inherited from System.Data.Common.DbDataReader)	Synchronously gets the value of the specified column as a type.
GetFieldValueAsync method (Inherited from System.Data.Common.DbDataReader)	Asynchronously gets the value of the specified column as a type.
GetFloat method	Returns the value for the specified column as a System.Single type.
GetGuid method	Returns the value for the specified column as a UUID (System.Guid) type.
GetInt16 method	Returns the value for the specified column as a System.Int16 type.
GetInt32 method	Returns the value for the specified column as a System.Int32 type.
GetInt64 method	Returns the value for the specified column as a System.Int64 type.
GetName method	Returns the name of the specified column.
GetOrdinal method	Returns the column ID of the named column.
GetProviderSpecificFieldType method (Inherited from System.Data.Common.DbDataReader)	Returns the provider-specific field type of the specified column.
GetProviderSpecificValue method (Inherited from System.Data.Common.DbDataReader)	Gets the value of the specified column as an instance of System.Object.
GetProviderSpecificValues method (Inherited from System.Data.Common.DbDataReader)	Gets all provider-specific attribute columns in the collection for the current row.
GetRowCount method	UL Ext: Returns the number of rows in the cursor, within threshold.
GetSchemaTable method	Returns a System.Data.DataTable value that describes the column metadata of the ULDataReader object.
GetStream method (Inherited from System.Data.Common.DbDataReader)	Retrieves data as a System.IO.Stream.
GetString method	Returns the value for the specified column as a System.String type.
GetTextReader method (Inherited from System.Data.Common.DbDataReader)	Retrieves data as a System.IO.TextReader.
GetTimeSpan method	Returns the value for the specified column as a System.TimeSpan type with millisecond accuracy.
GetUInt16 method	Returns the value for the specified column as a System.UInt16 type.
GetUInt32 method	Returns the value for the specified column as a System.UInt32 type.
GetUInt64 method	Returns the value for the specified column as a System.UInt64 type.
GetValue method	Returns the value of the specified column in its native format.
GetValues method	Returns all the column values for the current row.
IsDBNull method	Checks whether the value from the specified column is NULL.
IsDBNullAsync method (Inherited from System.Data.Common.DbDataReader)	An asynchronous version of System.Data.Common.DbDataReader.IsDBNull(System.Int32), which gets a value that indicates whether the column contains non-existent or missing values.
MoveAfterLast method	UL Ext: Positions the cursor to after the last row of the cursor.
MoveBeforeFirst method	UL Ext: Positions the cursor to before the first row of the cursor.
MoveFirst method	UL Ext: Positions the cursor to the first row of the cursor.
MoveLast method	UL Ext: Positions the cursor to the last row of the cursor.
MoveNext method	UL Ext: Positions the cursor to the next row or after the last row if the cursor was already on the last row.
MovePrevious method	UL Ext: Positions the cursor to the previous row or before the first row.
MoveRelative method	UL Ext: Positions the cursor relative to the current row.
NextResult method	Advances the ULDataReader object to the next result when reading the results of batch SQL statements.
NextResultAsync method (Inherited from System.Data.Common.DbDataReader)	An asynchronous version of System.Data.Common.DbDataReader.NextResult, which advances the reader to the next result when reading the results of a batch of statements.Invokes System.Data.Common.DbDataReader.NextResultAsync(System.Threading.CancellationToken) with CancellationToken.None.
Read method	Positions the cursor to the next row, or after the last row if the cursor was already on the last row.
ReadAsync method (Inherited from System.Data.Common.DbDataReader)	An asynchronous version of System.Data.Common.DbDataReader.Read, which advances the reader to the next record in a result set.
Depth property	Returns the depth of nesting for the current row.
FieldCount property	Returns the number of columns in the cursor.
HasRows property	Checks whether the ULDataReader object has one or more rows.
IsBOF property	UL Ext: Checks whether the current row position is before the first row.
IsClosed property	Checks whether the cursor is currently open.
IsEOF property	UL Ext: Checks whether the current row position is after the last row.
RecordsAffected property	Returns the number of rows changed, inserted, or deleted by execution of the SQL statement.
RowCount property	UL Ext: Returns the number of rows in the cursor.
Schema property	UL Ext: Holds the schema of this cursor.
this property	Returns the value of the specified column in its native format.
VisibleFieldCount property (Inherited from System.Data.Common.DbDataReader)	Gets the number of fields in the System.Data.Common.DbDataReader that are not hidden.

Remarks

Cursors are sets of rows from either a table or the result set from a query.

There is no constructor for the ULDataReader class. To get a ULDataReader object, execute a ULCommand object:

' Visual Basic
Dim cmd As ULCommand = new ULCommand( _
    "SELECT emp_id FROM employee", conn _
)
Dim reader As ULDataReader = cmd.ExecuteReader()

The following code is the C# language equivalent:

// C#
ULCommand cmd = new ULCommand(
    "SELECT emp_id FROM employee", conn
);
ULDataReader reader = cmd.ExecuteReader();

UL Ext: The ADO.NET standard only requires forward-only motion through the result set, but ULDataReader objects are bi-directional. ULDataReader's Move methods provide you with full flexibility when moving through results.

A ULDataReader object is a read-only result set. If you need a more flexible object to manipulate results, use the ULCommand.ExecuteResultSet method, the ULCommand.ExecuteTable method, or the ULDataAdapter class. The ULDataReader class retrieves rows as needed, whereas the ULDataAdapter class must retrieve all rows of a result set before you can carry out any action on the object. For large result sets, this difference gives the ULDataReader class a much faster response time.

UL Ext: All columns of a ULDataReader object may be retrieved using the GetString method.