IQueryResultSetTDataWhere(ExpressionFuncTData, Boolean) Method

Filter the result set where the specified condition matches

Namespace: SanteDB.Core.Model.Query
Assembly: SanteDB.Core.Model (in SanteDB.Core.Model.dll) Version: 3.0.2081-alpha+0a330d5f5a5d3cb3e6e945ef530e94ac5671b49c

Syntax

C++

Copy

IQueryResultSet<TData> Where(
	Expression<Func<TData, bool>> query
)

Function Where ( 
	query As Expression(Of Func(Of TData, Boolean))
) As IQueryResultSet(Of TData)

IQueryResultSet<TData>^ Where(
	Expression<Func<TData, bool>^>^ query
)

abstract Where : 
        query : Expression<Func<'TData, bool>> -> IQueryResultSet<'TData>

Parameters

query ExpressionFuncTData, Boolean: The query to apply

Return Value

IQueryResultSetTData
The filtered result collection

Exceptions

Exception	Condition
InvalidOperationException	When a WHERE clause has already been appended

Remarks

This instruction appends a SQL WHERE clause to your query. This can only be called once on a particular instance of a IQueryResultSetTData or else an invalid state is created. When calling directly from a persistence layer such as:


                var results = persistenceService.Query(o => o.StatusConceptKey == StatusKeys.Active, AuthenticationContext.Current.Princiapl);
                var filter = results.Where(o=> o.CreationTime > DateTime.Now); // invalid state

The method is intended for new result sets, for example, consider:


                var results = persistenceService.Query(o => o.StatusConceptKey == StatusKeys.Active, AuthenticationContext.Current.Princiapl);
                results = results.Union(o => o.StatusConceptKey.New);
                var filter = results.Where(o=> o.CreationTime > DateTime.Now);

Since the equivalent function in SQL is:


                SELECT *
                FROM (
                    SELECT *
                    FROM x
                    WHERE sts_cd_id = 'ACTIVE_UUID'
                    UNION
                    SELECT *
                    FROM x
                    WHERE sts_cd_id = 'NEW_UUID'
               ) I
               WHERE I.crt_utc > CURRENT_TIMESTAMP

Reference

IQueryResultSetTData Interface

Where Overload

SanteDB.Core.Model.Query Namespace