Class CqlQueryExtensions

Inheritance

object

CqlQueryExtensions

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Namespace: Cassandra.Data.Linq

Assembly: Cassandra.dll

Syntax

public static class CqlQueryExtensions

Methods

AllowFiltering<TSource>(CqlQuery<TSource>)

The ALLOW FILTERING option allows to explicitly allow queries that require filtering. Please note that a query using ALLOW FILTERING may thus have unpredictable performance (for the definition above), i.e. even a query that selects a handful of records may exhibit performance that depends on the total amount of data stored in the cluster.

Declaration

public static CqlQuery<TSource> AllowFiltering<TSource>(this CqlQuery<TSource> source)

Parameters

Type	Name	Description
CqlQuery<TSource>	source

Returns

Type	Description
CqlQuery<TSource>

Type Parameters

Name	Description
TSource

Count<TSource>(CqlQuery<TSource>)

Returns the number of rows matching the query. To execute this CqlScalar use Execute() method.

Declaration

public static CqlScalar<long> Count<TSource>(this CqlQuery<TSource> source)

Parameters

Type	Name	Description
CqlQuery<TSource>	source	The CqlQuery<TSource> to return the first element of.

Returns

Type	Description
CqlScalar<long>	A single result: the number of rows matching the query.

Type Parameters

Name	Description
TSource	The type of the elements of source.

DeleteIf<TSource>(CqlQuery<TSource>, Expression<Func<TSource, bool>>)

Returns a representation of a DELETE ... IF ... cql statement, for Lightweight Transactions support

Declaration

public static CqlConditionalCommand<TSource> DeleteIf<TSource>(this CqlQuery<TSource> source, Expression<Func<TSource, bool>> predicate)

Parameters

Type	Name	Description
CqlQuery<TSource>	source
Expression<Func<TSource, bool>>	predicate

Returns

Type	Description
CqlConditionalCommand<TSource>

Type Parameters

Name	Description
TSource

Delete<TSource>(CqlQuery<TSource>)

Returns a representation of a DELETE cql statement

Declaration

public static CqlDelete Delete<TSource>(this CqlQuery<TSource> source)

Parameters

Type	Name	Description
CqlQuery<TSource>	source

Returns

Type	Description
CqlDelete

Type Parameters

Name	Description
TSource

FirstOrDefault<TSource>(CqlQuery<TSource>)

Returns a CqlQuery which after execution will return the first element of a sequence, or a default value if the sequence contains no elements. To execute this CqlQuery use Execute() method.

Declaration

public static CqlQuerySingleElement<TSource> FirstOrDefault<TSource>(this CqlQuery<TSource> source)

Parameters

Type	Name	Description
CqlQuery<TSource>	source	The CqlQuery<TSource> to return the first element of.

Returns

Type	Description
CqlQuerySingleElement<TSource>	a CqlQuery<TSource> which after execution will return default(TSource) if source is empty, otherwise the first element in source.

Type Parameters

Name	Description
TSource	The type of the elements of source.

FirstOrDefault<TSource>(Table<TSource>, Expression<Func<TSource, bool>>)

Returns a CqlQuery which after execution will return the first element of the sequence that satisfies a condition or a default value if no such element is found. To execute this CqlQuery use Execute() method.

Declaration

public static CqlQuerySingleElement<TSource> FirstOrDefault<TSource>(this Table<TSource> source, Expression<Func<TSource, bool>> predicate)

Parameters

Type	Name	Description
Table<TSource>	source	The Table<TSource> to return the first element of.
Expression<Func<TSource, bool>>	predicate	A function to test each element for a condition.

Returns

Type	Description
CqlQuerySingleElement<TSource>	a CqlQuery<TSource> which after execution will return default(TSource) if source is empty or if no element passes the test specified by predicate, otherwise the first element in source that passes the test specified by predicate.

Type Parameters

Name	Description
TSource	The type of the elements of source.

First<TSource>(CqlQuery<TSource>)

Returns a CqlQuery which after execution will return the first element in a sequence. To execute this CqlQuery use Execute() method.

Declaration

public static CqlQuerySingleElement<TSource> First<TSource>(this CqlQuery<TSource> source)

Parameters

Type	Name	Description
CqlQuery<TSource>	source	The CqlQuery<TSource> to return the first element of.

Returns

Type	Description
CqlQuerySingleElement<TSource>	a CqlQuery<TSource> which after execution will return first element in the sequence.

Type Parameters

Name	Description
TSource	The type of the elements of source.

First<TSource>(Table<TSource>, Expression<Func<TSource, bool>>)

Returns a CqlQuery which after execution returns the first element in a sequence that satisfies a specified condition. To execute this CqlQuery use Execute() method.

Declaration

public static CqlQuerySingleElement<TSource> First<TSource>(this Table<TSource> source, Expression<Func<TSource, bool>> predicate)

Parameters

Type	Name	Description
Table<TSource>	source	The Table<TSource> to return the first element of.
Expression<Func<TSource, bool>>	predicate	A function to test each element for a condition.

Returns

Type	Description
CqlQuerySingleElement<TSource>	a CqlQuery<TSource> which after execution will return first element in the sequence that passes the test in the specified predicate function.

Type Parameters

Name	Description
TSource	The type of the elements of source.

GroupBy<TKey, TSource>(CqlQuery<TSource>, Expression<Func<TSource, TKey>>)

Returns a CqlQuery which after execution returns grouped sequence of values based on a predicate. To execute this CqlQuery use Execute() method.

Declaration

public static CqlQuery<IGrouping<TKey, TSource>> GroupBy<TKey, TSource>(this CqlQuery<TSource> source, Expression<Func<TSource, TKey>> predicate)

Parameters

Type	Name	Description
CqlQuery<TSource>	source	The CqlQuery<TSource> to filter.
Expression<Func<TSource, TKey>>	predicate	A function to test each element for a condition.

Returns

Type	Description
CqlQuery<IGrouping<TKey, TSource>>	a CqlQuery<TSource> which after execution will return an IEnumerable<TSource> that contains elements from the input sequence that satisfy the condition.

Type Parameters

Name	Description
TKey	The type of the value returned by selector.
TSource	The type of the elements of source.

OrderByDescending<TSource, TKey>(CqlQuery<TSource>, Expression<Func<TSource, TKey>>)

Sorts the elements, which are returned from CqlQuery, in ascending order according to a key.

Declaration

public static CqlQuery<TSource> OrderByDescending<TSource, TKey>(this CqlQuery<TSource> source, Expression<Func<TSource, TKey>> func)

Parameters

Type	Name	Description
CqlQuery<TSource>	source	A sequence of values to order, returned from CqlQuery<TSource>.
Expression<Func<TSource, TKey>>	func	A function to extract a key from an element.

Returns

Type	Description
CqlQuery<TSource>	a CqlQuery<TSource> which after execution returns an IEnumerable<TSource> sorted in descending manner according to a key.

Type Parameters

Name	Description
TSource	The type of the elements of source.
TKey	The type of the key returned by keySelector.

OrderBy<TSource, TKey>(CqlQuery<TSource>, Expression<Func<TSource, TKey>>)

Sorts the elements, which are returned from CqlQuery, in ascending order according to a key.

Declaration

public static CqlQuery<TSource> OrderBy<TSource, TKey>(this CqlQuery<TSource> source, Expression<Func<TSource, TKey>> keySelector)

Parameters

Type	Name	Description
CqlQuery<TSource>	source	A sequence of values to order, returned from CqlQuery<TSource>.
Expression<Func<TSource, TKey>>	keySelector	A function to extract a key from an element.

Returns

Type	Description
CqlQuery<TSource>	a CqlQuery<TSource> which after execution returns an IEnumerable<TSource> sorted in ascending manner according to a key.

Type Parameters

Name	Description
TSource	The type of the elements of source.
TKey	The type of the key returned by keySelector.

Select<TSource, TResult>(CqlQuery<TSource>, Expression<Func<TSource, TResult>>)

Projects each element of a sequence into a new form.

Declaration

public static CqlQuery<TResult> Select<TSource, TResult>(this CqlQuery<TSource> source, Expression<Func<TSource, TResult>> selector)

Parameters

Type	Name	Description
CqlQuery<TSource>	source	A CqlQuery<TSource> which after execution returns a sequence of values to invoke a transform function on.
Expression<Func<TSource, TResult>>	selector	A transform function to apply to each element.

Returns

Type	Description
CqlQuery<TResult>	a CqlQuery<TSource> which after execution will return an IEnumerable<TSource> whose elements are the result of invoking the transform function on each element of source. To execute this CqlQuery use Execute() method.

Type Parameters

Name	Description
TSource	The type of the elements of source.
TResult	The type of the value returned by selector.

Select<TGroup, TSource, TResult>(CqlQuery<IGrouping<TGroup, TSource>>, Expression<Func<IGrouping<TGroup, TSource>, TResult>>)

Declaration

public static CqlQuery<TResult> Select<TGroup, TSource, TResult>(this CqlQuery<IGrouping<TGroup, TSource>> source, Expression<Func<IGrouping<TGroup, TSource>, TResult>> selector)

Parameters

Type	Name	Description
CqlQuery<IGrouping<TGroup, TSource>>	source
Expression<Func<IGrouping<TGroup, TSource>, TResult>>	selector

Returns

Type	Description
CqlQuery<TResult>

Type Parameters

Name	Description
TGroup
TSource
TResult

Take<TSource>(CqlQuery<TSource>, int)

Returns a CqlQuery which after execution will return IEnumerable<TSource> with specified number of contiguous elements from the start of a sequence. To execute this CqlQuery use Execute() method.

Declaration

public static CqlQuery<TSource> Take<TSource>(this CqlQuery<TSource> source, int count)

Parameters

Type	Name	Description
CqlQuery<TSource>	source	The CqlQuery<TSource> to return the first element of.
int	count	The number of elements to return.

Returns

Type	Description
CqlQuery<TSource>	a CqlQuery<TSource> which after execution will return IEnumerable<TSource> with specified number of contiguous elements from the start of a sequence.

Type Parameters

Name	Description
TSource	The type of the elements of source.

ThenByDescending<TSource, TKey>(CqlQuery<TSource>, Expression<Func<TSource, TKey>>)

Sorts the elements, which are returned from CqlQuery, in descending order according to a key.

Declaration

public static CqlQuery<TSource> ThenByDescending<TSource, TKey>(this CqlQuery<TSource> source, Expression<Func<TSource, TKey>> func)

Parameters

Type	Name	Description
CqlQuery<TSource>	source
Expression<Func<TSource, TKey>>	func

Returns

Type	Description
CqlQuery<TSource>

Type Parameters

Name	Description
TSource
TKey

ThenBy<TSource, TKey>(CqlQuery<TSource>, Expression<Func<TSource, TKey>>)

Sorts the elements, which are returned from CqlQuery, in ascending order according to a key.

Declaration

public static CqlQuery<TSource> ThenBy<TSource, TKey>(this CqlQuery<TSource> source, Expression<Func<TSource, TKey>> func)

Parameters

Type	Name	Description
CqlQuery<TSource>	source
Expression<Func<TSource, TKey>>	func

Returns

Type	Description
CqlQuery<TSource>

Type Parameters

Name	Description
TSource
TKey

UpdateIfExists<TSource>(CqlQuery<TSource>)

Returns a representation of a UPDATE ... IF EXISTS cql statement, for Lightweight Transactions support.

Declaration

public static CqlConditionalCommand<TSource> UpdateIfExists<TSource>(this CqlQuery<TSource> source)

Parameters

Type	Name	Description
CqlQuery<TSource>	source

Returns

Type	Description
CqlConditionalCommand<TSource>

Type Parameters

Name	Description
TSource

UpdateIf<TSource>(CqlQuery<TSource>, Expression<Func<TSource, bool>>)

Returns a representation of a UPDATE ... IF ... cql statement, for Lightweight Transactions support

Declaration

public static CqlConditionalCommand<TSource> UpdateIf<TSource>(this CqlQuery<TSource> source, Expression<Func<TSource, bool>> predicate)

Parameters

Type	Name	Description
CqlQuery<TSource>	source
Expression<Func<TSource, bool>>	predicate

Returns

Type	Description
CqlConditionalCommand<TSource>

Type Parameters

Name	Description
TSource

Update<TSource>(CqlQuery<TSource>)

Returns a representation of a UPDATE cql statement

Declaration

public static CqlUpdate Update<TSource>(this CqlQuery<TSource> source)

Parameters

Type	Name	Description
CqlQuery<TSource>	source

Returns

Type	Description
CqlUpdate

Type Parameters

Name	Description
TSource

Where<TSource>(CqlQuery<TSource>, Expression<Func<TSource, bool>>)

Returns a CqlQuery which after execution returns filtered sequence of values based on a predicate. To execute this CqlQuery use Execute() method.

Declaration

public static CqlQuery<TSource> Where<TSource>(this CqlQuery<TSource> source, Expression<Func<TSource, bool>> predicate)

Parameters

Type	Name	Description
CqlQuery<TSource>	source	The CqlQuery<TSource> to filter.
Expression<Func<TSource, bool>>	predicate	A function to test each element for a condition.

Returns

Type	Description
CqlQuery<TSource>	a CqlQuery<TSource> which after execution will return an IEnumerable<TSource> that contains elements from the input sequence that satisfy the condition.

Type Parameters

Name	Description
TSource	The type of the elements of source.