Class CqlQueryExtensions

Inheritance
System.Object
CqlQueryExtensions
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()
Namespace: Dse.Data.Linq
Assembly: Dse.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<System.Int64>

A single result: the number of rows matching the query.
Type Parameters
Name Description
TSource

The type of the elements of source.

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

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

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
System.Linq.Expressions.Expression<System.Func<TSource, System.Boolean>> predicate
Returns
Type Description
CqlConditionalCommand<TSource>
Type Parameters
Name Description
TSource

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, Boolean>>)

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.
System.Linq.Expressions.Expression<System.Func<TSource, System.Boolean>> 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.

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, Boolean>>)

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.
System.Linq.Expressions.Expression<System.Func<TSource, System.Boolean>> 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.

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.
System.Linq.Expressions.Expression<System.Func<TSource, TKey>> predicate

A function to test each element for a condition.
Returns
Type Description
CqlQuery<System.Linq.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.

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>.
System.Linq.Expressions.Expression<System.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.

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>.
System.Linq.Expressions.Expression<System.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.

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.
System.Linq.Expressions.Expression<System.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<System.Linq.IGrouping<TGroup, TSource>> source
System.Linq.Expressions.Expression<System.Func<System.Linq.IGrouping<TGroup, TSource>, TResult>> selector
Returns
Type Description
CqlQuery<TResult>
Type Parameters
Name Description
TGroup
TSource
TResult

Take<TSource>(CqlQuery<TSource>, Int32)

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.
System.Int32 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.

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
System.Linq.Expressions.Expression<System.Func<TSource, TKey>> func
Returns
Type Description
CqlQuery<TSource>
Type Parameters
Name Description
TSource
TKey

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
System.Linq.Expressions.Expression<System.Func<TSource, TKey>> func
Returns
Type Description
CqlQuery<TSource>
Type Parameters
Name Description
TSource
TKey

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

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

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
System.Linq.Expressions.Expression<System.Func<TSource, System.Boolean>> predicate
Returns
Type Description
CqlConditionalCommand<TSource>
Type Parameters
Name Description
TSource

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

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

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.
System.Linq.Expressions.Expression<System.Func<TSource, System.Boolean>> 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.