Class DeephavenDataReader

Reads a forward-only stream of rows from a Deephaven data source.

Inheritance

System.Object

DeephavenDataReader

Namespace: Deephaven.Connector

Assembly: Deephaven.Connector.dll

Syntax

public class DeephavenDataReader : DbDataReader

Remarks

The class incrementally reads a consistent snapshot of a Deephaven table (in chunks consistent with the specified FetchSize). Ticking tables can be queried, but it does not provide streaming data.

Properties

Depth

Gets a value indicating the depth of nesting for the current row. Depth greater than zero not presently supported, will always return zero.

Declaration

public override int Depth { get; }

Property Value

Type	Description
System.Int32

FetchSize

Gets or sets the fetch size. Rows will be copied from the server in chunks according to this value. Default value is 10,000. Larger or smaller values may be optimal depending on memory, network and table properties (encoded size of data).

Declaration

public int FetchSize { get; set; }

Property Value

Type	Description
System.Int32

FieldCount

Gets the number of columns in the current row.

Declaration

public override int FieldCount { get; }

Property Value

Type	Description
System.Int32

HasRows

Gets a value that indicates whether this contains one or more rows.

Declaration

public override bool HasRows { get; }

Property Value

Type	Description
System.Boolean

IsClosed

Gets a value indicating whether the is closed.

Declaration

public override bool IsClosed { get; }

Property Value

Type	Description
System.Boolean

Item[Int32]

Gets the value of the specified column as an instance of Object.

Declaration

public override object this[int ordinal] { get; }

Parameters

Type	Name	Description
System.Int32	ordinal	The zero-based column ordinal.

Property Value

Type	Description
System.Object	The value of the specified column.

Item[String]

Gets the value of the specified column as an instance of Object.

Declaration

public override object this[string name] { get; }

Parameters

Type	Name	Description
System.String	name	The name of the column.

Property Value

Type	Description
System.Object	The value of the specified column.

RecordsAffected

Gets the number of rows changed, inserted, or deleted by execution of the statement. Since updates are not presently supported, always returns -1.

Declaration

public override int RecordsAffected { get; }

Property Value

Type	Description
System.Int32

Methods

Close()

Closes the DeephavenDataReader object.

Declaration

public override void Close()

GetBoolean(Int32)

Gets the value of the specified column as a Boolean.

Declaration

public override bool GetBoolean(int ordinal)

Parameters

Type	Name	Description
System.Int32	ordinal	The zero-based column ordinal.

Returns

Type	Description
System.Boolean	The value of the specified column.

GetByte(Int32)

Gets the value of the specified column as a byte.

Declaration

public override byte GetByte(int ordinal)

Parameters

Type	Name	Description
System.Int32	ordinal	The zero-based column ordinal.

Returns

Type	Description
System.Byte	The value of the specified column.

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

Reads a specified number of bytes from the specified column starting at a specified index and writes them to a buffer starting at a specified position in the buffer.

Declaration

public override long GetBytes(int ordinal, long dataOffset, byte[] buffer, int bufferOffset, int length)

Parameters

Type	Name	Description
System.Int32	ordinal	The zero-based column ordinal.
System.Int64	dataOffset	The index within the row from which to begin the read operation.
System.Byte[]	buffer	The buffer into which to copy the data.
System.Int32	bufferOffset	The index with the buffer to which the data will be copied.
System.Int32	length	The maximum number of characters to read.

Returns

Type	Description
System.Int64	The actual number of bytes read.

GetChar(Int32)

Gets the value of the specified column as a char.

Declaration

public override char GetChar(int ordinal)

Parameters

Type	Name	Description
System.Int32	ordinal	The zero-based column ordinal.

Returns

Type	Description
System.Char	The value of the specified column.

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

Reads a specified number of characters from a specified column starting at a specified index, and writes them to a buffer starting at a specified position.

Declaration

public override long GetChars(int ordinal, long dataOffset, char[] buffer, int bufferOffset, int length)

Parameters

Type	Name	Description
System.Int32	ordinal	The zero-based column ordinal.
System.Int64	dataOffset	The index within the row from which to begin the read operation.
System.Char[]	buffer	The buffer into which to copy the data.
System.Int32	bufferOffset	The index with the buffer to which the data will be copied.
System.Int32	length	The maximum number of characters to read.

Returns

Type	Description
System.Int64	The actual number of characters read.

GetDataTypeName(Int32)

Gets name of the data type of the specified column.

Declaration

public override string GetDataTypeName(int ordinal)

Parameters

Type	Name	Description
System.Int32	ordinal	The zero-based column ordinal.

Returns

Type	Description
System.String	The name of the data type.

GetDateTime(Int32)

Gets the value of the specified column as a DateTime.

Declaration

public override DateTime GetDateTime(int ordinal)

Parameters

Type	Name	Description
System.Int32	ordinal	The zero-based column ordinal.

Returns

Type	Description
DateTime	The value of the specified column.

GetDecimal(Int32)

Gets the value of the specified column as a decimal.

Declaration

public override decimal GetDecimal(int ordinal)

Parameters

Type	Name	Description
System.Int32	ordinal	The zero-based column ordinal.

Returns

Type	Description
System.Decimal	The value of the specified column.

GetDouble(Int32)

Gets the value of the specified column as a double.

Declaration

public override double GetDouble(int ordinal)

Parameters

Type	Name	Description
System.Int32	ordinal	The zero-based column ordinal.

Returns

Type	Description
System.Double	The value of the specified column.

GetEnumerator()

Returns an enumerator that can be used to iterate through the rows in the data reader.

Declaration

public override IEnumerator GetEnumerator()

Returns

Type	Description
IEnumerator	An enumerator that can be used to iterate through the rows in the data reader.

GetFieldType(Int32)

Gets the data type of the specified column.

Declaration

public override Type GetFieldType(int ordinal)

Parameters

Type	Name	Description
System.Int32	ordinal	The zero-based column ordinal.

Returns

Type	Description
Type	The data type of the specified column.

GetFloat(Int32)

Gets the value of the specified column as a float.

Declaration

public override float GetFloat(int ordinal)

Parameters

Type	Name	Description
System.Int32	ordinal	The zero-based column ordinal.

Returns

Type	Description
System.Single	The value of the specified column.

GetGuid(Int32)

Gets the value of the specified column as a Guid.

Declaration

public override Guid GetGuid(int ordinal)

Parameters

Type	Name	Description
System.Int32	ordinal	The zero-based column ordinal.

Returns

Type	Description
Guid	The value of the specified column.

GetInt16(Int32)

Gets the value of the specified column as a 16-bit signed integer.

Declaration

public override short GetInt16(int ordinal)

Parameters

Type	Name	Description
System.Int32	ordinal	The zero-based column ordinal.

Returns

Type	Description
System.Int16	The value of the specified column.

GetInt32(Int32)

Gets the value of the specified column as a 32-bit signed integer.

Declaration

public override int GetInt32(int ordinal)

Parameters

Type	Name	Description
System.Int32	ordinal	The zero-based column ordinal.

Returns

Type	Description
System.Int32	The value of the specified column.

GetInt64(Int32)

Gets the value of the specified column as a 64-bit signed integer.

Declaration

public override long GetInt64(int ordinal)

Parameters

Type	Name	Description
System.Int32	ordinal	The zero-based column ordinal.

Returns

Type	Description
System.Int64	The value of the specified column.

GetName(Int32)

Gets the name of the column, given the zero-based column ordinal.

Declaration

public override string GetName(int ordinal)

Parameters

Type	Name	Description
System.Int32	ordinal	The zero-based column ordinal.

Returns

Type	Description
System.String	The name of the specified column.

GetOrdinal(String)

Gets the column ordinal given the name of the column.

Declaration

public override int GetOrdinal(string name)

Parameters

Type	Name	Description
System.String	name	The name of the column.

Returns

Type	Description
System.Int32	The zero-based column ordinal.

GetString(Int32)

Gets the value of the specified column as a string.

Declaration

public override string GetString(int ordinal)

Parameters

Type	Name	Description
System.Int32	ordinal	The zero-based column ordinal.

Returns

Type	Description
System.String	The value of the specified column.

GetValue(Int32)

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

Declaration

public override object GetValue(int ordinal)

Parameters

Type	Name	Description
System.Int32	ordinal	The zero-based column ordinal.

Returns

Type	Description
System.Object	The value of the specified column.

GetValues(Object[])

Populates an array of objects with the column values of the current row.

Declaration

public override int GetValues(object[] values)

Parameters

Type	Name	Description
System.Object[]	values	An array of into which to copy the attribute columns.

Returns

Type	Description
System.Int32	The number of instances of in the array.

IsDBNull(Int32)

Gets a value that indicates whether the column contains nonexistent or missing values.

Declaration

public override bool IsDBNull(int ordinal)

Parameters

Type	Name	Description
System.Int32	ordinal	The zero-based column ordinal.

Returns

Type	Description
System.Boolean	true if the specified column is equivalent to ; otherwise, false .

NextResult()

Advances the reader to the next result when reading the results of a batch of statements.

Declaration

public override bool NextResult()

Returns

Type	Description
System.Boolean	true if there are more result sets; otherwise, false .

Read()

Advances the reader to the next record in a result set.

Declaration

public override bool Read()

Returns

Type	Description
System.Boolean	true if there are more rows; otherwise, false .