Table of Contents

Class SqlProviderFlags

Namespace
LinqToDB.Internal.SqlProvider
Assembly
linq2db.dll
[DataContract]
public sealed class SqlProviderFlags
Inheritance
SqlProviderFlags
Inherited Members
Extension Methods

Constructors

SqlProviderFlags() 

public SqlProviderFlags()

Properties

AcceptsOuterExpressionInAggregate

Provider supports aggregated expression with Outer reference

SELECT
(
	SELECT SUM(inner.FieldX + outer.FieldOuter)
	FROM table2 inner
) AS Sum_Column
FROM table1 outer

Otherwise aggeragated expression will be wrapped in subquery and aggregate function will be applied to subquery column.

SELECT
(
	SELECT
		SUM(sub.Column)
	FROM
		(
			SELECT inner.FieldX + outer.FieldOuter AS Column
			FROM table2 inner
		) sub
) AS Sum_Column
FROM table1 outer

Default (set by DataProviderBase): true.

[DataMember(Order = 33)]
public bool AcceptsOuterExpressionInAggregate { get; set; }

Property Value

bool

AcceptsTakeAsParameter

Indicates that TAKE/TOP/LIMIT could accept parameter. Default (set by DataProviderBase): true.

[DataMember(Order = 3)]
public bool AcceptsTakeAsParameter { get; set; }

Property Value

bool

AcceptsTakeAsParameterIfSkip

Indicates that TAKE/LIMIT could accept parameter only if also SKIP/OFFSET specified. Default (set by DataProviderBase): false.

[DataMember(Order = 4)]
public bool AcceptsTakeAsParameterIfSkip { get; set; }

Property Value

bool

CalculateSupportedCorrelatedLevelWithAggregateQueries

Gets or sets a value indicating whether the calculation of deep level includes aggregation queries. Works in conjunction with SupportedCorrelatedSubqueriesLevel.

[DataMember(Order = 57)]
public bool CalculateSupportedCorrelatedLevelWithAggregateQueries { get; set; }

Property Value

bool

CanCombineParameters

Indicates that provider could share parameter between statements in multi-statement batch. Default (set by DataProviderBase): true.

[DataMember(Order = 22)]
public bool CanCombineParameters { get; set; }

Property Value

bool

CustomFlags

Flags for use by external providers.

[DataMember(Order = 1)]
public HashSet<string> CustomFlags { get; set; }

Property Value

HashSet<string>

DefaultMultiQueryIsolationLevel

Used when there is query which needs several additional database requests for completing query (e.g. eager load or client-side GroupBy). Default (set by DataProviderBase): RepeatableRead.

[DataMember(Order = 37)]
public IsolationLevel DefaultMultiQueryIsolationLevel { get; set; }

Property Value

IsolationLevel

DoesProviderTreatsEmptyStringAsNull

Provider treats empty string as null in queries. It is specific behaviour only for Oracle. Default false

[DataMember(Order = 30)]
public bool DoesProviderTreatsEmptyStringAsNull { get; set; }

Property Value

bool

IsAccessBuggyLeftJoinConstantNullability

Indicates that provider has bug in LEFT join translator. In the following example can_be_null is always not null, which is wrong.

SELECT
	can_be_null
FROM Some
LEFT JOIN 1 as can_be_null, * FROM Other
	ON ...

As workaround translator is trying to check for nullability all projected fields. Default value: false.

[DataMember(Order = 48)]
public bool IsAccessBuggyLeftJoinConstantNullability { get; set; }

Property Value

bool

IsAllSetOperationsSupported

Provider supports EXCEPT ALL, INTERSECT ALL set operators. Otherwise they will be emulated. Default (set by DataProviderBase): false.

[DataMember(Order = 31)]
public bool IsAllSetOperationsSupported { get; set; }

Property Value

bool

IsApplyJoinSupported

Indicates support for OUTER/CROSS APPLY. Default (set by DataProviderBase): false.

[DataMember(Order = 18)]
public bool IsApplyJoinSupported { get; set; }

Property Value

bool

IsCTESupportsOrdering

Indicates that top level CTE query supports ORDER BY. Default value: true.

[DataMember(Order = 47)]
public bool IsCTESupportsOrdering { get; set; }

Property Value

bool

IsColumnSubqueryShouldNotContainParentIsNotNull

Workaround over Oracle's bug with subquery in column list which contains parent table column with IS NOT NULL condition. Default value: false.

[DataMember(Order = 43)]
public bool IsColumnSubqueryShouldNotContainParentIsNotNull { get; set; }

Property Value

bool

Remarks

See Issue3557Case1 test.

IsColumnSubqueryWithParentReferenceAndTakeSupported

Provider supports column subqueries which references outer scope when nesting is more than 1

[DataMember(Order = 42)]
public bool IsColumnSubqueryWithParentReferenceAndTakeSupported { get; set; }

Property Value

bool

Remarks

Used only for Oracle 11. linq2db emulates Take(n) via 'ROWNUM' and it causes additional nesting. Default value: true.

IsCommonTableExpressionsSupported

Indicates support of CTE expressions. If provider does not support CTE, unsuported exception will be thrown when using CTE. Default (set by DataProviderBase): false.

[DataMember(Order = 29)]
public bool IsCommonTableExpressionsSupported { get; set; }

Property Value

bool

IsComplexJoinConditionSupported

When disabled, all conditions from INNER JOIN ON moved to WHERE except conjunction of equality predicates.

FROM T1 INNER JOIN T2 ON t1.field1 == t2.field1 AND t1.field2 == t2.field2 AND t1.field3 > 10
-- with flag:
FROM T1 INNER JOIN T2 ON t1.field1 == t2.field1 AND t1.field2 == t2.field2
WHERE t1.field3 > 10

Default: true.

[DataMember(Order = 60)]
public bool IsComplexJoinConditionSupported { get; set; }

Property Value

bool

IsCorrelatedSubQueryTakeSupported

Indicates support for paging clause in correlated subquery. Default (set by DataProviderBase): true.

[DataMember(Order = 11)]
public bool IsCorrelatedSubQueryTakeSupported { get; set; }

Property Value

bool

IsCountSubQuerySupported

Indicates that database supports count subquery as scalar in column.

SELECT (SELECT COUNT(*) FROM some_table) FROM ...

Default (set by DataProviderBase): true.

[DataMember(Order = 16)]
public bool IsCountSubQuerySupported { get; set; }

Property Value

bool

IsCrossApplyJoinSupportsCondition

Indicates support for CROSS APPLY supports condition LATERAL JOIN for example. Default (set by DataProviderBase): false.

[DataMember(Order = 19)]
public bool IsCrossApplyJoinSupportsCondition { get; set; }

Property Value

bool

IsCrossJoinSupported

Indicates support for CROSS JOIN. Default (set by DataProviderBase): true.

[DataMember(Order = 28)]
public bool IsCrossJoinSupported { get; set; }

Property Value

bool

IsCrossJoinSyntaxRequired

When enabled, always prefer "FROM T1 CROSS JOIN T2" over "FROM T1, T2" join syntax. Default: false.

[DataMember(Order = 61)]
public bool IsCrossJoinSyntaxRequired { get; set; }

Property Value

bool

IsDerivedTableOrderBySupported

Provider supports SUM/AVG/MIN/MAX(DISTINCT column) function. Otherwise, it will be emulated. Default (set by DataProviderBase): true.

[DataMember(Order = 52)]
public bool IsDerivedTableOrderBySupported { get; set; }

Property Value

bool

IsDerivedTableTakeSupported

Indicates support for paging clause in derived table. Default (set by DataProviderBase): true.

[DataMember(Order = 9)]
public bool IsDerivedTableTakeSupported { get; set; }

Property Value

bool

IsDistinctFromSupported

Provider supports correlated DISTINCT FROM directly or through db-specific operator/method (e.g. DECODE, IS, <=>). This doesn't include emulation using INTERSECT. Default false

[DataMember(Order = 58)]
public bool IsDistinctFromSupported { get; set; }

Property Value

bool

IsDistinctSetOperationsSupported

Provider supports EXCEPT, INTERSECT set operators. Otherwise it will be emulated. Default (set by DataProviderBase): true.

[DataMember(Order = 32)]
public bool IsDistinctSetOperationsSupported { get; set; }

Property Value

bool

IsExistsPreferableForContains

Default value: false.

[DataMember(Order = 39)]
public bool IsExistsPreferableForContains { get; set; }

Property Value

bool

IsIdentityParameterRequired

Indicates that provider requires explicit output parameter for insert with identity queries to get identity from database. Default (set by DataProviderBase): false.

[DataMember(Order = 17)]
public bool IsIdentityParameterRequired { get; set; }

Property Value

bool

IsInsertOrUpdateSupported

Indicates support for single-query insert-or-update operation support. Otherwise two separate queries used to emulate operation (update, then insert if nothing found to update). Default (set by DataProviderBase): true.

[DataMember(Order = 21)]
public bool IsInsertOrUpdateSupported { get; set; }

Property Value

bool

IsJoinDerivedTableWithTakeInvalid

Indicates that provider has issue with any JOIN to subquery which has TOP statement. Default false.

[DataMember(Order = 10)]
public bool IsJoinDerivedTableWithTakeInvalid { get; set; }

Property Value

bool

Remarks

Currently use as workaround over Sybase bug.

IsMultiTablesSupportsJoins

Indicates that provider supports JOINS in FROM clause which have several tables

SELECT ...
FROM table1
   INNER JOIN query ON ...
   , table2

Otherwise the following query will be generated:

SELECT ...
FROM (
	SELECT ...
	FROM table1, table2
) S
   INNER JOIN query ON ... ,
FROM table2

Default: true. Currently not supported only by Access. 

[DataMember(Order = 46)]
public bool IsMultiTablesSupportsJoins { get; set; }

Property Value

bool

IsNamingQueryBlockSupported

Provider supports Naming Query Blocks

QB_NAME(qb)

Default (set by DataProviderBase): false.

[DataMember(Order = 35)]
public bool IsNamingQueryBlockSupported { get; set; }

Property Value

bool

IsNestedJoinsSupported

Provider supports nested joins

A JOIN (B JOIN C ON ?) ON ?

otherwise nested join replaced with sub-query

A JOIN (SELECT ? FROM B JOIN C ON ?) ON ?
.

Default (set by DataProviderBase): true.

[DataMember(Order = 51)]
public bool IsNestedJoinsSupported { get; set; }

Property Value

bool

IsOrderByAggregateFunctionSupported

Provider supports Aggregate function in ORDER BY. Default (set by DataProviderBase): true.

[DataMember(Order = 59)]
public bool IsOrderByAggregateFunctionSupported { get; set; }

Property Value

bool

Remarks

Applied only to SqlCe provider.

IsOuterApplyJoinSupportsCondition

Indicates support for OUTER APPLY supports condition LATERAL JOIN for example. Default (set by DataProviderBase): false.

[DataMember(Order = 20)]
public bool IsOuterApplyJoinSupportsCondition { get; set; }

Property Value

bool

IsOuterJoinSupportsInnerJoin

Provider supports INNER JOIN inside OUTER JOIN. For example:

LEFT JOIN table1 ON ...
   INNER JOIN query ON ...

Otherwise the following query will be left:

LEFT JOIN (
   SELECT ...
   FROM table1
   INNER JOIN query ON ...
)

Default: true. Currently not supported only by Access. 

[DataMember(Order = 45)]
public bool IsOuterJoinSupportsInnerJoin { get; set; }

Property Value

bool

IsParameterOrderDependent

Indicates that provider (not database!) uses positional parameters instead of named parameters (parameter values assigned in order they appear in query, not by parameter name). Default (set by DataProviderBase): false.

[DataMember(Order = 2)]
public bool IsParameterOrderDependent { get; set; }

Property Value

bool

IsRecursiveCTEJoinWithConditionSupported

Provider supports INNER JOIN with condition inside Recursive CTE, currently not supported only by DB2 Default value: true.

[DataMember(Order = 44)]
public bool IsRecursiveCTEJoinWithConditionSupported { get; set; }

Property Value

bool

IsRowNumberWithoutOrderBySupported

Provider supports ROW_NUMBER OVER () without ORDER BY Default value: true.

[DataMember(Order = 40)]
public bool IsRowNumberWithoutOrderBySupported { get; set; }

Property Value

bool

IsSkipSupported

Indicates support for SKIP/OFFSET paging clause (parameter) without TAKE clause. Provider could set this flag even if database not support it if emulates missing functionality. E.g. : TAKE [MAX_ALLOWED_VALUE] SKIP skip_value Default (set by DataProviderBase): true.

[DataMember(Order = 5)]
public bool IsSkipSupported { get; set; }

Property Value

bool

IsSkipSupportedIfTake

Indicates support for SKIP/OFFSET paging clause (parameter) only if also TAKE/LIMIT specified. Default (set by DataProviderBase): false.

[DataMember(Order = 6)]
public bool IsSkipSupportedIfTake { get; set; }

Property Value

bool

IsSubQueryColumnSupported

Indicates support for scalar subquery in select list. E.g. SELECT (SELECT TOP 1 value FROM some_table) AS MyColumn, ... Default (set by DataProviderBase): true.

[DataMember(Order = 14)]
public bool IsSubQueryColumnSupported { get; set; }

Property Value

bool

IsSubQueryOrderBySupported

Indicates support of ORDER BY clause in sub-queries. Default (set by DataProviderBase): false.

[DataMember(Order = 15)]
public bool IsSubQueryOrderBySupported { get; set; }

Property Value

bool

IsSubQuerySkipSupported

Indicates support for skip clause in column expression subquery. Default (set by DataProviderBase): true.

[DataMember(Order = 13)]
public bool IsSubQuerySkipSupported { get; set; }

Property Value

bool

IsSubQueryTakeSupported

Indicates support for paging clause in subquery. Default (set by DataProviderBase): true.

[DataMember(Order = 8)]
public bool IsSubQueryTakeSupported { get; set; }

Property Value

bool

IsSubqueryWithParentReferenceInJoinConditionSupported

Provider supports condition in subquery which references parent table Default value: true.

[DataMember(Order = 41)]
public bool IsSubqueryWithParentReferenceInJoinConditionSupported { get; set; }

Property Value

bool

IsSupportedSimpleCorrelatedSubqueries

Provider supports correlated subqueris, which can be easily converted to JOIN. Default (set by DataProviderBase): false.

[DataMember(Order = 55)]
public bool IsSupportedSimpleCorrelatedSubqueries { get; set; }

Property Value

bool

Remarks

Applied only to ClickHouse provider.

IsSupportsJoinWithoutCondition

Indicates that provider supports JOIN without condition ON 1=1. Default (set by DataProviderBase): true.

[DataMember(Order = 12)]
public bool IsSupportsJoinWithoutCondition { get; set; }

Property Value

bool

IsUpdateFromSupported

Indicates support for following UPDATE syntax:

UPDATE A
SET ...
FROM B

Default (set by DataProviderBase): true.

[DataMember(Order = 34)]
public bool IsUpdateFromSupported { get; set; }

Property Value

bool

IsUpdateSkipTakeSupported

Provider supports SKIP+TAKE limit for UPDATE query. Default (set by DataProviderBase): false.

[DataMember(Order = 54)]
public bool IsUpdateSkipTakeSupported { get; set; }

Property Value

bool

IsUpdateTakeSupported

Provider supports TAKE limit for UPDATE query. Default (set by DataProviderBase): false.

[DataMember(Order = 53)]
public bool IsUpdateTakeSupported { get; set; }

Property Value

bool

IsWindowFunctionsSupported

Indicates that provider supports window functions. Default value: true.

[DataMember(Order = 36)]
public bool IsWindowFunctionsSupported { get; set; }

Property Value

bool

MaxInListValuesCount

Specifies limit of number of values in single IN predicate without splitting it into several IN's. Default (set by DataProviderBase): int.MaxValue (basically means there is no limit).

[DataMember(Order = 23)]
public int MaxInListValuesCount { get; set; }

Property Value

int

OutputDeleteUseSpecialTable

If true, removed record fields in OUTPUT clause of DELETE statement should be referenced using table with special name (e.g. DELETED or OLD). Otherwise fields should be referenced using target table. Default (set by DataProviderBase): false.

[DataMember(Order = 24)]
public bool OutputDeleteUseSpecialTable { get; set; }

Property Value

bool

OutputInsertUseSpecialTable

If true, added record fields in OUTPUT clause of INSERT statement should be referenced using table with special name (e.g. INSERTED or NEW). Otherwise fields should be referenced using target table. Default (set by DataProviderBase): false.

[DataMember(Order = 25)]
public bool OutputInsertUseSpecialTable { get; set; }

Property Value

bool

OutputMergeUseSpecialTables

If true, OUTPUT clause supports both OLD and NEW data in MERGE statement using tables with special names. Otherwise only current record fields (after all changes) available using target table. Default (set by DataProviderBase): false.

[DataMember(Order = 27)]
public bool OutputMergeUseSpecialTables { get; set; }

Property Value

bool

OutputUpdateUseSpecialTables

If true, OUTPUT clause supports both OLD and NEW data in UPDATE statement using tables with special names. Otherwise only current record fields (after update) available using target table. Default (set by DataProviderBase): false.

[DataMember(Order = 26)]
public bool OutputUpdateUseSpecialTables { get; set; }

Property Value

bool

RowConstructorSupport

Provider support Row Constructor (1, 2, 3) in various positions (flags) Default (set by DataProviderBase): None.

[DataMember(Order = 38)]
public RowFeature RowConstructorSupport { get; set; }

Property Value

RowFeature

SupportedCorrelatedSubqueriesLevel

Provider supports correlated subqueris, but limited how deep in subquery outer reference Default null. If this value is 0c>, provider do not support correlated subqueries

[DataMember(Order = 56)]
public int? SupportedCorrelatedSubqueriesLevel { get; set; }

Property Value

int?

SupportsBooleanType

Indicates that boolean type could be used as predicate without additional conversions. Default value: true.

[DataMember(Order = 50)]
public bool SupportsBooleanType { get; set; }

Property Value

bool

SupportsPredicatesComparison

Indicates that provider supports direct comparison of predicates. Default value: false.

[DataMember(Order = 49)]
public bool SupportsPredicatesComparison { get; set; }

Property Value

bool

TakeHintsSupported

Indicates supported TAKE/LIMIT hints. Default (set by DataProviderBase): null (none).

[DataMember(Order = 7)]
public TakeHints? TakeHintsSupported { get; set; }

Property Value

TakeHints?

Methods

Equals(object?) 

public override bool Equals(object? obj)

Parameters

obj object

Returns

bool

GetAcceptsTakeAsParameterFlag(SelectQuery) 

public bool GetAcceptsTakeAsParameterFlag(SelectQuery selectQuery)

Parameters

selectQuery SelectQuery

Returns

bool

GetHashCode() 

public override int GetHashCode()

Returns

int

GetIsSkipSupportedFlag(ISqlExpression?) 

public bool GetIsSkipSupportedFlag(ISqlExpression? takeExpression)

Parameters

takeExpression ISqlExpression

Returns

bool

GetIsTakeHintsSupported(TakeHints) 

public bool GetIsTakeHintsSupported(TakeHints hints)

Parameters

hints TakeHints

Returns

bool