Google.Cloud.Spanner.Data - Class SpannerDataReader (4.5.0)

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

Reference documentation and code samples for the Google.Cloud.Spanner.Data class SpannerDataReader.

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

Inheritance

object > MarshalByRefObject > DbDataReader > SpannerDataReader

Implements

IEnumerable, IDataReader, IDataRecord, IDisposable, IAsyncDisposable

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

Properties

Depth

public override int Depth { get; }

Property Value
Type	Description
`int`

Overrides

DbDataReader.Depth

FieldCount

public override int FieldCount { get; }

Property Value
Type	Description
`int`

Overrides

DbDataReader.FieldCount

HasRows

public override bool HasRows { get; }

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.

Property Value
Type	Description
`bool`

Overrides

DbDataReader.HasRows

IsClosed

public override bool IsClosed { get; }

Property Value
Type	Description
`bool`

Overrides

DbDataReader.IsClosed

this[int]

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

Parameter
Name	Description
`i`	`int`

Property Value
Type	Description
`object`

Overrides

DbDataReader.this[int]

this[string]

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

Parameter
Name	Description
`name`	`string`

Property Value
Type	Description
`object`

Overrides

DbDataReader.this[string]

RecordsAffected

public override int RecordsAffected { get; }

Property Value
Type	Description
`int`

Overrides

DbDataReader.RecordsAffected

Methods

Close()

public override void Close()

Overrides

DbDataReader.Close()

Dispose(bool)

protected override void Dispose(bool disposing)

Parameter
Name	Description
`disposing`	`bool`

Overrides

DbDataReader.Dispose(bool)

GetBoolean(int)

public override bool GetBoolean(int i)

Parameter
Name	Description
`i`	`int`

Returns
Type	Description
`bool`

Overrides

DbDataReader.GetBoolean(int)

GetByte(int)

public override byte GetByte(int i)

Parameter
Name	Description
`i`	`int`

Returns
Type	Description
`byte`

Overrides

DbDataReader.GetByte(int)

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

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

Parameters
Name	Description
`ordinal`	`int`
`fieldOffset`	`long`
`buffer`	`byte`
`bufferOffset`	`int`
`length`	`int`

Returns
Type	Description
`long`

Overrides

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

GetChar(int)

public override char GetChar(int i)

Parameter
Name	Description
`i`	`int`

Returns
Type	Description
`char`

Overrides

DbDataReader.GetChar(int)

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

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

Parameters
Name	Description
`i`	`int`
`fieldoffset`	`long`
`buffer`	`char`
`bufferoffset`	`int`
`length`	`int`

Returns
Type	Description
`long`

Overrides

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

GetDataTypeName(int)

public override string GetDataTypeName(int i)

Parameter
Name	Description
`i`	`int`

Returns
Type	Description
`string`

Overrides

DbDataReader.GetDataTypeName(int)

GetDateTime(int)

public override DateTime GetDateTime(int i)

Parameter
Name	Description
`i`	`int`

Returns
Type	Description
`DateTime`

Overrides

DbDataReader.GetDateTime(int)

GetDecimal(int)

public override decimal GetDecimal(int i)

Parameter
Name	Description
`i`	`int`

Returns
Type	Description
`decimal`

Overrides

DbDataReader.GetDecimal(int)

GetDouble(int)

public override double GetDouble(int i)

Parameter
Name	Description
`i`	`int`

Returns
Type	Description
`double`

Overrides

DbDataReader.GetDouble(int)

GetEnumerator()

public override IEnumerator GetEnumerator()

Returns
Type	Description
`IEnumerator`

Overrides

DbDataReader.GetEnumerator()

GetFieldType(int)

public override Type GetFieldType(int i)

Parameter
Name	Description
`i`	`int`

Returns
Type	Description
`Type`

Overrides

DbDataReader.GetFieldType(int)

GetFieldValue<T>(int)

public override T GetFieldValue<T>(int ordinal)

Parameter
Name	Description
`ordinal`	`int`

Returns
Type	Description
`T`

Type Parameter
Name	Description
`T`

Overrides

DbDataReader.GetFieldValue<T>(int)

GetFieldValue<T>(string)

public T GetFieldValue<T>(string columnName)

Gets the value of the specified column as type T.

Parameter
Name	Description
`columnName`	`string` 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 Parameter

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)

public override float GetFloat(int i)

Parameter
Name	Description
`i`	`int`

Returns
Type	Description
`float`

Overrides

DbDataReader.GetFloat(int)

GetGuid(int)

public override Guid GetGuid(int i)

Parameter
Name	Description
`i`	`int`

Returns
Type	Description
`Guid`

Overrides

DbDataReader.GetGuid(int)

GetInt16(int)

public override short GetInt16(int i)

Parameter
Name	Description
`i`	`int`

Returns
Type	Description
`short`

Overrides

DbDataReader.GetInt16(int)

GetInt32(int)

public override int GetInt32(int i)

Parameter
Name	Description
`i`	`int`

Returns
Type	Description
`int`

Overrides

DbDataReader.GetInt32(int)

GetInt64(int)

public override long GetInt64(int i)

Parameter
Name	Description
`i`	`int`

Returns
Type	Description
`long`

Overrides

DbDataReader.GetInt64(int)

GetJsonValue(int)

public Value GetJsonValue(int i)

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

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

Returns
Type	Description
`Value`	The raw protobuf as a Value.

Exceptions
Type	Description
`InvalidOperationException`	The reader is not currently positioned on a valid row.

GetName(int)

public override string GetName(int i)

Parameter
Name	Description
`i`	`int`

Returns
Type	Description
`string`

Overrides

DbDataReader.GetName(int)

GetNumeric(int)

public SpannerNumeric GetNumeric(int i)

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

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

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

GetOrdinal(string)

public override int GetOrdinal(string name)

Parameter
Name	Description
`name`	`string`

Returns
Type	Description
`int`

Overrides

DbDataReader.GetOrdinal(string)

GetOrdinalAsync(string, CancellationToken)

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

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

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

Returns
Type	Description
`Taskint`	The zero-based column ordinal.

GetPgNumeric(int)

public PgNumeric GetPgNumeric(int i)

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

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

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

GetReadTimestamp()

public Timestamp GetReadTimestamp()

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

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)

public Task<Timestamp> GetReadTimestampAsync(CancellationToken cancellationToken)

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

Parameter
Name	Description
`cancellationToken`	`CancellationToken`

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

GetSchemaTable()

public override DataTable 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.

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)

public SpannerDate GetSpannerDate(int i)

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

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

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

GetString(int)

public override string GetString(int i)

Parameter
Name	Description
`i`	`int`

Returns
Type	Description
`string`

Overrides

DbDataReader.GetString(int)

GetTimestamp(int)

public Timestamp GetTimestamp(int i)

Gets the value of the specified column as type Timestamp.

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

Returns
Type	Description
`Timestamp`	The value converted to a Timestamp.

GetValue(int)

public override object GetValue(int i)

Parameter
Name	Description
`i`	`int`

Returns
Type	Description
`object`

Overrides

DbDataReader.GetValue(int)

GetValues(object[])

public override int GetValues(object[] values)

Parameter
Name	Description
`values`	`object`

Returns
Type	Description
`int`

Overrides

DbDataReader.GetValues(object[])

IsDBNull(int)

public override bool IsDBNull(int i)

Parameter
Name	Description
`i`	`int`

Returns
Type	Description
`bool`

Overrides

DbDataReader.IsDBNull(int)

NextResult()

public override bool NextResult()

Returns
Type	Description
`bool`

Overrides

DbDataReader.NextResult()

Read()

public override bool Read()

Returns
Type	Description
`bool`

Overrides

DbDataReader.Read()

ReadAsync(CancellationToken)

public override Task<bool> ReadAsync(CancellationToken cancellationToken)

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

Parameter
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
`Taskbool`	True if another row was read.

Overrides

DbDataReader.ReadAsync(CancellationToken)