Class ParquetDataReader

The ParquetDataReader class enables forward-only reading of data from a Parquet file, implementing the System.Data.IDataReader interface. If you need to interact with a ParquetDataReader directly, you can process all the data from a Parquet File using a while loop like this:

var reader = new ParquetDataReader(stream); while (reader.Read()) { // Process the data }

Namespace: Workspace.XBR.Xperiflow.Etl.Tabular

Assembly: Xperiflow.dll

Declaration

public class ParquetDataReader : IDataReader, IDataRecord, IDisposable

Implements: System.Data.IDataReader, System.Data.IDataRecord, System.IDisposable

Properties

this[int]

Gets the column located at the specified index.

Declaration

public object this[int i] { get; }

this[string]

Gets the column with the specified name.

Declaration

public object this[string name] { get; }

Depth

Returns 0 for a ParquetDataReader

Declaration

public int Depth { get; }

IsClosed

Gets a value indicating whether the data reader is closed.

Declaration

public bool IsClosed { get; }

RecordsAffected

Returns 0 for a ParquetDataReader

Declaration

public int RecordsAffected { get; }

FieldCount

Gets the number of columns in the current row.

Declaration

public int FieldCount { get; }

Methods

Read()

Advances the System.Data.IDataReader to the next record.

Declaration

public bool Read()

Returns

System.Boolean

true if there are more rows; otherwise, false.

IsDBNull(int)

Return whether the specified field is set to null.

Declaration

public bool IsDBNull(int i)

Returns

System.Boolean

true if the specified field is set to null; otherwise, false.

Parameters

Type	Name	Description
System.Int32	i	The index of the field to find.

Exceptions

System.IndexOutOfRangeException The index passed was outside the range of 0 through System.Data.IDataRecord.FieldCount.

GetValue(int)

Return the value of the specified field.

Declaration

public object GetValue(int i)

Returns

System.Object

The System.Object which will contain the field value upon return.

Parameters

Type	Name	Description
System.Int32	i	The index of the field to find.

Exceptions

System.IndexOutOfRangeException The index passed was outside the range of 0 through System.Data.IDataRecord.FieldCount.

GetOrdinal(string)

Return the index of the named field.

Declaration

public int GetOrdinal(string name)

Returns

System.Int32

The index of the named field.

Parameters

Type	Name	Description
System.String	name	The name of the field to find.

GetName(int)

Gets the name for the field to find.

Declaration

public string GetName(int i)

Returns

System.String

The name of the field or the empty string (""), if there is no value to return.

Parameters

Type	Name	Description
System.Int32	i	The index of the field to find.

Exceptions

System.IndexOutOfRangeException The index passed was outside the range of 0 through System.Data.IDataRecord.FieldCount.

GetFieldType(int)

Gets the System.Type information corresponding to the type of System.Object that would be returned from System.Data.IDataRecord.GetValue(System.Int32).

Declaration

public Type GetFieldType(int i)

Returns

System.Type

The System.Type information corresponding to the type of System.Object that would be returned from System.Data.IDataRecord.GetValue(System.Int32).

Parameters

Type	Name	Description
System.Int32	i	The index of the field to find.

Exceptions

System.IndexOutOfRangeException The index passed was outside the range of 0 through System.Data.IDataRecord.FieldCount.

GetBoolean(int)

Gets the value of the specified column as a Boolean.

Declaration

public bool GetBoolean(int i)

Returns

System.Boolean

The value of the column.

Parameters

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

Exceptions

System.IndexOutOfRangeException The index passed was outside the range of 0 through System.Data.IDataRecord.FieldCount.

GetByte(int)

Gets the 8-bit unsigned integer value of the specified column.

Declaration

public byte GetByte(int i)

Returns

System.Byte

The 8-bit unsigned integer value of the specified column.

Parameters

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

Exceptions

System.IndexOutOfRangeException The index passed was outside the range of 0 through System.Data.IDataRecord.FieldCount.

GetBytes(int, long, byte[], int, int)

Reads a stream of bytes from the specified column offset into the buffer as an array, starting at the given buffer offset.

Declaration

public long GetBytes(int i, long fieldOffset, byte[] buffer, int bufferoffset, int length)

Returns

System.Int64

The actual number of bytes read.

Parameters

Type	Name	Description
System.Int32	i	The zero-based column ordinal.
System.Int64	fieldOffset	The index within the field from which to start the read operation.
System.Byte[]	buffer	The buffer into which to read the stream of bytes.
System.Int32	bufferoffset	The index for buffer to start the read operation.
System.Int32	length	The number of bytes to read.

Exceptions

System.IndexOutOfRangeException The index passed was outside the range of 0 through System.Data.IDataRecord.FieldCount.

GetChar(int)

Gets the character value of the specified column.

Declaration

public char GetChar(int i)

Returns

System.Char

The character value of the specified column.

Parameters

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

Exceptions

System.IndexOutOfRangeException The index passed was outside the range of 0 through System.Data.IDataRecord.FieldCount.

GetChars(int, long, char[], int, int)

Reads a stream of characters from the specified column offset into the buffer as an array, starting at the given buffer offset.

Declaration

public long GetChars(int i, long fieldoffset, char[] buffer, int bufferoffset, int length)

Returns

System.Int64

The actual number of characters read.

Parameters

Type	Name	Description
System.Int32	i	The zero-based column ordinal.
System.Int64	fieldoffset	The index within the row from which to start the read operation.
System.Char[]	buffer	The buffer into which to read the stream of bytes.
System.Int32	bufferoffset	The index for buffer to start the read operation.
System.Int32	length	The number of bytes to read.

Exceptions

System.IndexOutOfRangeException The index passed was outside the range of 0 through System.Data.IDataRecord.FieldCount.

GetData(int)

Not implemented for Parquet

Declaration

public IDataReader GetData(int i)

Returns

System.Data.IDataReader

Not Supported Exception

Parameters

Type	Name
System.Int32	i

Exceptions

System.NotSupportedException

GetDataTypeName(int)

Gets the data type information for the specified field.

Declaration

public string GetDataTypeName(int i)

Returns

System.String

The data type information for the specified field.

Parameters

Type	Name	Description
System.Int32	i	The index of the field to find.

Exceptions

System.IndexOutOfRangeException The index passed was outside the range of 0 through System.Data.IDataRecord.FieldCount.

GetDateTime(int)

Gets the date and time data value of the specified field.

Declaration

public DateTime GetDateTime(int i)

Returns

System.DateTime

The date and time data value of the specified field.

Parameters

Type	Name	Description
System.Int32	i	The index of the field to find.

Exceptions

System.IndexOutOfRangeException The index passed was outside the range of 0 through System.Data.IDataRecord.FieldCount.

GetDecimal(int)

Gets the fixed-position numeric value of the specified field.

Declaration

public decimal GetDecimal(int i)

Returns

System.Decimal

The fixed-position numeric value of the specified field.

Parameters

Type	Name	Description
System.Int32	i	The index of the field to find.

Exceptions

System.IndexOutOfRangeException The index passed was outside the range of 0 through System.Data.IDataRecord.FieldCount.

GetDouble(int)

Gets the double-precision floating point number of the specified field.

Declaration

public double GetDouble(int i)

Returns

System.Double

The double-precision floating point number of the specified field.

Parameters

Type	Name	Description
System.Int32	i	The index of the field to find.

Exceptions

System.IndexOutOfRangeException The index passed was outside the range of 0 through System.Data.IDataRecord.FieldCount.

GetFloat(int)

Gets the single-precision floating point number of the specified field.

Declaration

public float GetFloat(int i)

Returns

System.Single

The single-precision floating point number of the specified field.

Parameters

Type	Name	Description
System.Int32	i	The index of the field to find.

Exceptions

System.IndexOutOfRangeException The index passed was outside the range of 0 through System.Data.IDataRecord.FieldCount.

GetGuid(int)

Returns the GUID value of the specified field.

Declaration

public Guid GetGuid(int i)

Returns

System.Guid

The GUID value of the specified field.

Parameters

Type	Name	Description
System.Int32	i	The index of the field to find.

Exceptions

System.IndexOutOfRangeException The index passed was outside the range of 0 through System.Data.IDataRecord.FieldCount.

GetInt16(int)

Gets the 16-bit signed integer value of the specified field.

Declaration

public short GetInt16(int i)

Returns

System.Int16

The 16-bit signed integer value of the specified field.

Parameters

Type	Name	Description
System.Int32	i	The index of the field to find.

Exceptions

System.IndexOutOfRangeException The index passed was outside the range of 0 through System.Data.IDataRecord.FieldCount.

GetInt32(int)

Gets the 32-bit signed integer value of the specified field.

Declaration

public int GetInt32(int i)

Returns

System.Int32

The 32-bit signed integer value of the specified field.

Parameters

Type	Name	Description
System.Int32	i	The index of the field to find.

Exceptions

System.IndexOutOfRangeException The index passed was outside the range of 0 through System.Data.IDataRecord.FieldCount.

GetInt64(int)

Gets the 64-bit signed integer value of the specified field.

Declaration

public long GetInt64(int i)

Returns

System.Int64

The 64-bit signed integer value of the specified field.

Parameters

Type	Name	Description
System.Int32	i	The index of the field to find.

Exceptions

System.IndexOutOfRangeException The index passed was outside the range of 0 through System.Data.IDataRecord.FieldCount.

GetValues(object[])

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

Declaration

public int GetValues(object[] values)

Returns

System.Int32

The number of instances of System.Object in the array.

Parameters

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

GetString(int)

Gets the string value of the specified field.

Declaration

public string GetString(int i)

Returns

System.String

The string value of the specified field.

Parameters

Type	Name	Description
System.Int32	i	The index of the field to find.

Exceptions

System.IndexOutOfRangeException The index passed was outside the range of 0 through System.Data.IDataRecord.FieldCount.

GetSchemaTable()

Returns a System.Data.DataTable that describes the column metadata of the System.Data.IDataReader.

Returns null if the executed command returned no resultset, or after System.Data.IDataReader.NextResult returns false.

Declaration

public DataTable GetSchemaTable()

Returns

System.Data.DataTable

A System.Data.DataTable that describes the column metadata.

Exceptions

System.InvalidOperationException The System.Data.IDataReader is closed.

NextResult()

Returns false for a ParquetDataReader

Declaration

public bool NextResult()

Returns

System.Boolean

false

Close()

Closes the System.Data.IDataReader Object.

Declaration

public void Close()

Dispose(bool)

Disposes the ParquetDataReader object.

Declaration

protected virtual void Dispose(bool disposing)

Parameters

Type	Name
System.Boolean	disposing

Dispose()

Disposes the ParquetDataReader object.

Declaration

public void Dispose()

Implements

• System.Data.IDataReader
• System.Data.IDataRecord
• System.IDisposable

Inherited Members

• System.Object.Equals(System.Object)
• System.Object.Equals(System.Object,System.Object)
• System.Object.GetHashCode
• System.Object.GetType
• System.Object.MemberwiseClone
• System.Object.ReferenceEquals(System.Object,System.Object)
• System.Object.ToString