Class SpannerDataReader

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

Inheritance

object

MarshalByRefObject

DbDataReader

SpannerDataReader

Implements

Inherited Members

DbDataReader.CloseAsync()

DbDataReader.DisposeAsync()

DbDataReader.GetFieldValueAsync<T>(int)

DbDataReader.GetFieldValueAsync<T>(int, CancellationToken)

DbDataReader.GetStream(int)

DbDataReader.GetTextReader(int)

DbDataReader.IsDBNullAsync(int)

DbDataReader.IsDBNullAsync(int, CancellationToken)

DbDataReader.NextResultAsync()

DbDataReader.NextResultAsync(CancellationToken)

DbDataReader.ReadAsync()

DbDataReader.VisibleFieldCount

MarshalByRefObject.GetLifetimeService()

MarshalByRefObject.InitializeLifetimeService()

object.GetHashCode()

object.GetType()

object.ToString()

Namespace: Google.Cloud.Spanner.Data

Assembly: Google.Cloud.Spanner.Data.dll

Syntax

public sealed class SpannerDataReader : DbDataReader, IEnumerable, IDataReader, IDataRecord, IDisposable, IAsyncDisposable

Properties

Depth

Gets a value indicating the depth of nesting for the current row.

Declaration

public override int Depth { get; }

Property Value

Type	Description
int	The depth of nesting for the current row.

Overrides

DbDataReader.Depth

FieldCount

Gets the number of columns in the current row.

Declaration

public override int FieldCount { get; }

Property Value

Type	Description
int	The number of columns in the current row.

Overrides

DbDataReader.FieldCount

Exceptions

Type	Condition
NotSupportedException	There is no current connection to an instance of SQL Server.

HasRows

Gets a value that indicates whether the SpannerDataReader contains one or more rows. If any rows have been read, this will continue to return true even when there are no more rows.

Declaration

public override bool HasRows { get; }

Property Value

Type	Description
bool

Overrides

DbDataReader.HasRows

IsClosed

Gets a value indicating whether the DbDataReader is closed.

Declaration

public override bool IsClosed { get; }

Property Value

Type	Description
bool	true if the DbDataReader is closed; otherwise, false.

Overrides

DbDataReader.IsClosed

Exceptions

Type	Condition
InvalidOperationException	The DbDataReader is closed.

this[int]

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

Declaration

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

Parameters

Type	Name	Description
int	i

Property Value

Type	Description
object	The value of the specified column.

Overrides

DbDataReader.this[int]

Exceptions

Type	Condition
IndexOutOfRangeException	The column index is out of range.

this[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
string	name	The name of the column.

Property Value

Type	Description
object	The value of the specified column.

Overrides

DbDataReader.this[string]

Exceptions

Type	Condition
IndexOutOfRangeException	No column with the specified name was found.

RecordsAffected

Gets the number of rows changed, inserted, or deleted by execution of the SQL statement.

Declaration

public override int RecordsAffected { get; }

Property Value

Type	Description
int	The number of rows changed, inserted, or deleted. -1 for SELECT statements; 0 if no rows were affected or the statement failed.

Overrides

DbDataReader.RecordsAffected

Methods

Close()

Closes the DbDataReader object.

Declaration

public override void Close()

Overrides

DbDataReader.Close()

Dispose(bool)

Releases the managed resources used by the DbDataReader and optionally releases the unmanaged resources.

Declaration

protected override void Dispose(bool disposing)

Parameters

Type	Name	Description
bool	disposing	true to release managed and unmanaged resources; false to release only unmanaged resources.

Overrides

DbDataReader.Dispose(bool)

GetBoolean(int)

Gets the value of the specified column as a Boolean.

Declaration

public override bool GetBoolean(int i)

Parameters

Type	Name	Description
int	i

Returns

Type	Description
bool	The value of the specified column.

Overrides

DbDataReader.GetBoolean(int)

Exceptions

Type	Condition
IndexOutOfRangeException	The column index is out of range.
InvalidCastException	The specified cast is not valid.

GetByte(int)

Gets the value of the specified column as a byte.

Declaration

public override byte GetByte(int i)

Parameters

Type	Name	Description
int	i

Returns

Type	Description
byte	The value of the specified column.

Overrides

DbDataReader.GetByte(int)

Exceptions

Type	Condition
IndexOutOfRangeException	The column index is out of range.
InvalidCastException	The specified cast is not valid.

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

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 fieldOffset, byte[] buffer, int bufferOffset, int length)

Parameters

Type	Name	Description
int	ordinal	The zero-based column ordinal.
long	fieldOffset
byte[]	buffer	The buffer into which to copy the data.
int	bufferOffset	The index with the buffer to which the data will be copied.
int	length	The maximum number of characters to read.

Returns

Type	Description
long	The actual number of bytes read.

Overrides

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

Exceptions

Type	Condition
IndexOutOfRangeException	The column index is out of range.
InvalidCastException	The specified cast is not valid.

GetChar(int)

Gets the value of the specified column as a single character.

Declaration

public override char GetChar(int i)

Parameters

Type	Name	Description
int	i

Returns

Type	Description
char	The value of the specified column.

Overrides

DbDataReader.GetChar(int)

Exceptions

Type	Condition
IndexOutOfRangeException	The column index is out of range.
InvalidCastException	The specified cast is not valid.

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

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

Parameters

Type	Name	Description
int	i
long	fieldoffset
char[]	buffer	The buffer into which to copy the data.
int	bufferoffset
int	length	The maximum number of characters to read.

Returns

Type	Description
long	The actual number of characters read.

Overrides

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

GetDataTypeName(int)

Gets name of the data type of the specified column.

Declaration

public override string GetDataTypeName(int i)

Parameters

Type	Name	Description
int	i

Returns

Type	Description
string	The name of the data type.

Overrides

DbDataReader.GetDataTypeName(int)

Exceptions

Type	Condition
IndexOutOfRangeException	The column index is out of range.

GetDateTime(int)

Gets the value of the specified column as a DateTime object.

Declaration

public override DateTime GetDateTime(int i)

Parameters

Type	Name	Description
int	i

Returns

Type	Description
DateTime	The value of the specified column.

Overrides

DbDataReader.GetDateTime(int)

Exceptions

Type	Condition
IndexOutOfRangeException	The column index is out of range.
InvalidCastException	The specified cast is not valid.

GetDecimal(int)

Gets the value of the specified column as a decimal.

Declaration

public override decimal GetDecimal(int i)

Parameters

Type	Name	Description
int	i

Returns

Type	Description
decimal	The value of the specified column.

Overrides

DbDataReader.GetDecimal(int)

Exceptions

Type	Condition
IndexOutOfRangeException	The column index is out of range.
InvalidCastException	The specified cast is not valid.

GetDouble(int)

Gets the value of the specified column as a double-precision floating point number.

Declaration

public override double GetDouble(int i)

Parameters

Type	Name	Description
int	i

Returns

Type	Description
double	The value of the specified column.

Overrides

DbDataReader.GetDouble(int)

Exceptions

Type	Condition
InvalidCastException	The specified cast is not valid.

GetEnumerator()

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

Declaration

public override IEnumerator GetEnumerator()

Returns

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

Overrides

DbDataReader.GetEnumerator()

GetFieldType(int)

Gets the data type of the specified column.

Declaration

public override Type GetFieldType(int i)

Parameters

Type	Name	Description
int	i

Returns

Type	Description
Type	The data type of the specified column.

Overrides

DbDataReader.GetFieldType(int)

Exceptions

Type	Condition
IndexOutOfRangeException	The column index is out of range.
InvalidCastException	The specified cast is not valid.

GetFieldValue<T>(int)

Gets the value of the specified column as the requested type.

Declaration

public override T GetFieldValue<T>(int ordinal)

Parameters

Type	Name	Description
int	ordinal	The zero-based column ordinal.

Returns

Type	Description
T	The value of the specified column.

Type Parameters

Name	Description
T	The type of the value to be returned.

Overrides

DbDataReader.GetFieldValue<T>(int)

Exceptions

Type	Condition
InvalidOperationException	The connection was dropped or closed during data retrieval. -or- The data reader was closed during data retrieval. -or- There is no data ready to be read (for example, the first Read() hasn't been called, or it returned false). -or- The reader tried to read a previously-read column in sequential mode. -or- There was an asynchronous operation in progress. This applies to all Get* methods when running in sequential mode, as they could be called while reading a stream.
IndexOutOfRangeException	The column index is out of range.
InvalidCastException	The value returned by the database doesn't match or cannot be cast to T.

GetFieldValue<T>(string)

Gets the value of the specified column as type T.

Declaration

public T GetFieldValue<T>(string columnName)

Parameters

Type	Name	Description
string	columnName	The name of the column whose value will be returned. Must not be null.

Returns

Type	Description
T	The value of the column at the current row, converted to type T.

Type Parameters

Name	Description
T	The expected return type. If possible the return type will be converted to this type. If conversion is requested between incompatible types, an InvalidOperationException will be thrown. If the conversion fails due to the contents returned (for example a string representing a boolean does not have either 'true' or 'false') then a FormatException exception will be thrown as documented by the Convert class.

GetFloat(int)

Gets the value of the specified column as a single-precision floating point number.

Declaration

public override float GetFloat(int i)

Parameters

Type	Name	Description
int	i

Returns

Type	Description
float	The value of the specified column.

Overrides

DbDataReader.GetFloat(int)

Exceptions

Type	Condition
IndexOutOfRangeException	The column index is out of range.
InvalidCastException	The specified cast is not valid.

GetGuid(int)

Gets the value of the specified column as a globally unique identifier (GUID).

Declaration

public override Guid GetGuid(int i)

Parameters

Type	Name	Description
int	i

Returns

Type	Description
Guid	The value of the specified column.

Overrides

DbDataReader.GetGuid(int)

Exceptions

Type	Condition
IndexOutOfRangeException	The column index is out of range.
InvalidCastException	The specified cast is not valid.

GetInt16(int)

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

Declaration

public override short GetInt16(int i)

Parameters

Type	Name	Description
int	i

Returns

Type	Description
short	The value of the specified column.

Overrides

DbDataReader.GetInt16(int)

Exceptions

Type	Condition
IndexOutOfRangeException	The column index is out of range.
InvalidCastException	The specified cast is not valid.

GetInt32(int)

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

Declaration

public override int GetInt32(int i)

Parameters

Type	Name	Description
int	i

Returns

Type	Description
int	The value of the specified column.

Overrides

DbDataReader.GetInt32(int)

Exceptions

Type	Condition
IndexOutOfRangeException	The column index is out of range.
InvalidCastException	The specified cast is not valid.

GetInt64(int)

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

Declaration

public override long GetInt64(int i)

Parameters

Type	Name	Description
int	i

Returns

Type	Description
long	The value of the specified column.

Overrides

DbDataReader.GetInt64(int)

Exceptions

Type	Condition
IndexOutOfRangeException	The column index is out of range.
InvalidCastException	The specified cast is not valid.

GetJsonValue(int)

Gets the value of the specified column as a pure Protobuf type.

Declaration

public Value GetJsonValue(int i)

Parameters

Type	Name	Description
int	i	The index of the column whose value will be returned.

Returns

Type	Description
Value	The raw protobuf as a Value.

Exceptions

Type	Condition
InvalidOperationException	The reader is not currently positioned on a valid row.

GetName(int)

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

Declaration

public override string GetName(int i)

Parameters

Type	Name	Description
int	i

Returns

Type	Description
string	The name of the specified column.

Overrides

DbDataReader.GetName(int)

GetNumeric(int)

Gets the value of the specified column as type Google.Cloud.Spanner.V1.SpannerNumeric.

Declaration

public SpannerNumeric GetNumeric(int i)

Parameters

Type	Name	Description
int	i	The index of the column to retrieve.

Returns

Type	Description
SpannerNumeric	The value converted to a Google.Cloud.Spanner.V1.SpannerNumeric.

GetOrdinal(string)

Gets the column ordinal given the name of the column.

Declaration

public override int GetOrdinal(string name)

Parameters

Type	Name	Description
string	name	The name of the column.

Returns

Type	Description
int	The zero-based column ordinal.

Overrides

DbDataReader.GetOrdinal(string)

Exceptions

Type	Condition
IndexOutOfRangeException	The name specified is not a valid column name.

GetOrdinalAsync(string, CancellationToken)

Returns the column ordinal given the name of the column, asynchronously requesting metadata from the database if necessary.

Declaration

public Task<int> GetOrdinalAsync(string name, CancellationToken cancellationToken = default)

Parameters

Type	Name	Description
string	name	The name of the column.
CancellationToken	cancellationToken	A cancellation token to cancel reading metadata. Defaults to None.

Returns

Type	Description
Task<int>	The zero-based column ordinal.

GetPgNumeric(int)

Gets the value of the specified column as type Google.Cloud.Spanner.V1.PgNumeric.

Declaration

public PgNumeric GetPgNumeric(int i)

Parameters

Type	Name	Description
int	i	The index of the column to retrieve.

Returns

Type	Description
PgNumeric	The value converted to a Google.Cloud.Spanner.V1.PgNumeric.

GetReadTimestamp()

Gets the read timestamp if ReturnReadTimestamp was true else returns null.

Declaration

public Timestamp GetReadTimestamp()

Returns

Type	Description
Timestamp	The value converted to a Timestamp, or `null` if ReturnReadTimestamp was false.

Remarks

The read timestamp can be read before Read() or ReadAsync(CancellationToken) is called.

GetReadTimestampAsync(CancellationToken)

Gets the read timestamp if ReturnReadTimestamp was true else returns null.

Declaration

public Task<Timestamp> GetReadTimestampAsync(CancellationToken cancellationToken)

Parameters

Type	Name	Description
CancellationToken	cancellationToken

Returns

Type	Description
Task<Timestamp>	The value converted to a Timestamp, or `null` if ReturnReadTimestamp was false.

GetSchemaTable()

When enabled, returns the schema of the query as a DataTable. This feature needs to be enabled in the connection string via the EnableGetSchemaTable property.

Declaration

public override DataTable GetSchemaTable()

Returns

Type	Description
DataTable	A `DataTable` with schema information about the query, or `null` if the feature is not enabled in the connection string.

Overrides

DbDataReader.GetSchemaTable()

Remarks

DbDataAdapter will use this method automatically, but there is not enough information available for it to do so to reliably manage data sets. This method returns null by default to avoid this causing problems.

When the EnableGetSchemaTable property in the connection string is set to true, a DataTable is returned with the following columns populated:

ColumnName (String): The name of the column
ColumnOrdinal (Int32): The ordinal value of the column
DataType (Type): The default CLR type of the column
ProviderType (SpannerDbType): The Spanner-specific data type of the column

The following additional columns are present in the table, but not currently populated:

ColumnSize
NumericPrecision
NumericScale

Future releases may expand the set of columns, or populate more of the existing columns.

GetSpannerDate(int)

Gets the value of the specified column as type Google.Cloud.Spanner.V1.SpannerDate.

Declaration

public SpannerDate GetSpannerDate(int i)

Parameters

Type	Name	Description
int	i	The index of the column to retrieve.

Returns

Type	Description
SpannerDate	The value converted to a Google.Cloud.Spanner.V1.SpannerDate.

GetString(int)

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

Declaration

public override string GetString(int i)

Parameters

Type	Name	Description
int	i

Returns

Type	Description
string	The value of the specified column.

Overrides

DbDataReader.GetString(int)

Exceptions

Type	Condition
IndexOutOfRangeException	The column index is out of range.
InvalidCastException	The specified cast is not valid.

GetTimestamp(int)

Gets the value of the specified column as type Timestamp.

Declaration

public Timestamp GetTimestamp(int i)

Parameters

Type	Name	Description
int	i	The index of the column to retrieve.

Returns

Type	Description
Timestamp	The value converted to a Timestamp.

GetValue(int)

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

Declaration

public override object GetValue(int i)

Parameters

Type	Name	Description
int	i

Returns

Type	Description
object	The value of the specified column.

Overrides

DbDataReader.GetValue(int)

Exceptions

Type	Condition
IndexOutOfRangeException	The column index is out of range.

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
object[]	values	An array of object into which to copy the attribute columns.

Returns

Type	Description
int	The number of instances of object in the array.

Overrides

DbDataReader.GetValues(object[])

IsDBNull(int)

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

Declaration

public override bool IsDBNull(int i)

Parameters

Type	Name	Description
int	i

Returns

Type	Description
bool	true if the specified column is equivalent to DBNull; otherwise, false.

Overrides

DbDataReader.IsDBNull(int)

Exceptions

Type	Condition
IndexOutOfRangeException	The column index is out of range.

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
bool	true if there are more result sets; otherwise, false.

Overrides

DbDataReader.NextResult()

Read()

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

Declaration

public override bool Read()

Returns

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

Overrides

DbDataReader.Read()

ReadAsync(CancellationToken)

Reads the next row of values from Cloud Spanner. Important: Cloud Spanner supports limited cancellation of this task.

Declaration

public override Task<bool> ReadAsync(CancellationToken cancellationToken)

Parameters

Type	Name	Description
CancellationToken	cancellationToken	A cancellation token to cancel the read. Cloud Spanner currently supports limited cancellation while advancing the read to the next row.

Returns

Type	Description
Task<bool>	True if another row was read.

Overrides

DbDataReader.ReadAsync(CancellationToken)