Relation Protocol Reference

scheme
The relation’s scheme.
Declaration
Swift

var scheme: Scheme { get }
debugName
The debug name for the Relation, which can be handy for identifying them in debug dumps.
Declaration
Swift

var debugName: String? { get set }
contains(_:)
Return true if the given row is contained in the Relation, and false if not.
Declaration
Swift

func contains(_ row: Row) -> Result<Bool, RelationError>

Core relational algebra

project(_:) Default implementation
Undocumented

Default Implementation

Undocumented

Undocumented
Declaration
Swift

func project(_ scheme: Scheme) -> Relation
project(dropping:) Default implementation
Undocumented

Default Implementation

Returns a projection of this Relation that includes only those attributes that appear in this Relation’s scheme but not in the given scheme.
Declaration
Swift

func project(dropping scheme: Scheme) -> Relation


                    
                    
                    project(_:)

Undocumented

Declaration

Swift

func project(_ attribute: Attribute) -> Relation

select(_:) Default implementation
Perform a select operation with a query defined by the contents of a Row. The resulting query is equivalent to ANDing together an equality expression for each attribute in the row, requiring it to be equal to that value in the row.

Default Implementation

Undocumented

Undocumented
Declaration
Swift

func select(_ rowToFind: Row) -> Relation
select(_:)
Perform a select operation with the given query.
Declaration
Swift

func select(_ query: SelectExpression) -> Relation
renameAttributes(_:) Default implementation
Return a new Relation that renames the Attributes in the keys of renames to the corresponding values.

Default Implementation
Declaration
Swift

func renameAttributes(_ renames: [Attribute : Attribute]) -> Relation
renamePrime() Default implementation
Undocumented

Default Implementation

Undocumented
Declaration
Swift

func renamePrime() -> Relation
projectRenamed(_:) Default implementation
Return a new Relation that projects and renames the Attributes in the keys of renames to the corresponding values. This is a shorthand for project followed by renameAttributes.

Default Implementation
Declaration
Swift

func projectRenamed(_ renames: [Attribute : Attribute]) -> Relation
union(_:) Default implementation
Return a new Relation which represents the union of this Relation and another one.

Default Implementation
Declaration
Swift

func union(_ other: Relation) -> Relation
intersection(_:) Default implementation
Return a new Relation which represents the intersection of this Relation and another one.

Default Implementation
Declaration
Swift

func intersection(_ other: Relation) -> Relation
difference(_:) Default implementation
Return a new Relation which represents the difference of this Relation and another one.

Default Implementation
Declaration
Swift

func difference(_ other: Relation) -> Relation
join(_:) Default implementation
Return a new Relation which represents the join of this Relation and another one. This is equivalent to an equijoin where the matches are equal to the intersection of the two schemes.

Default Implementation
Declaration
Swift

func join(_ other: Relation) -> Relation


                    
                    
                    equijoin(_:matching:)

Default implementation

Return a new Relation which represents the join of this Relation and another one, matching the values for the attributes given in the matching parameter.

Default Implementation

Declaration

Swift

func equijoin(_ other: Relation, matching: [Attribute : Attribute]) -> Relation

Parameters

`other`	The Relation to join with.
`matching`	A dictionary which describes the matches to perform for the join. The value for the key `Attribute` in this `Relation` will be matched with the value for the value `Attribute` in `other`.

thetajoin(_:query:) Default implementation
Undocumented

Default Implementation

Undocumented
Declaration
Swift

func thetajoin(_ other: Relation, query: SelectExpression) -> Relation
split(_:) Default implementation
Undocumented

Default Implementation

Undocumented
Declaration
Swift

func split(_ query: SelectExpression) -> (Relation, Relation)
divide(_:) Default implementation
Undocumented

Default Implementation

Undocumented
Declaration
Swift

func divide(_ other: Relation) -> Relation

Relational algebra extensions

leftOuterJoin(_:) Default implementation
Undocumented

Default Implementation

Undocumented
Declaration
Swift

func leftOuterJoin(_ other: Relation) -> Relation

Aggregate operations

min(_:) Default implementation
Undocumented

Default Implementation

Undocumented
Declaration
Swift

func min(_ attribute: Attribute) -> Relation
max(_:) Default implementation
Undocumented

Default Implementation

Undocumented
Declaration
Swift

func max(_ attribute: Attribute) -> Relation
count() Default implementation
Undocumented

Default Implementation

Undocumented
Declaration
Swift

func count() -> Relation

Experimental operations

otherwise(_:) Default implementation
Return a new Relation that resolves to this Relation when it is non-empty, otherwise resolves to the other Relation.

Default Implementation
Declaration
Swift

func otherwise(_ other: Relation) -> Relation
unique(_:matching:) Default implementation
Return a new Relation that resolves to this Relation when there is a unique value for the given attribute that is the same as matching, otherwise resolves to an empty Relation.

Default Implementation
Declaration
Swift

func unique(_ attribute: Attribute, matching: RelationValue) -> Relation

Synchronous updates

withUpdate(_:newValues:) Default implementation
Return a new Relation which represents this Relation with the given updates applied to all rows that match the query.

Default Implementation
Declaration
Swift

func withUpdate(_ query: SelectExpression, newValues: Row) -> Relation
withUpdate(_:) Default implementation
Return a new Relation which represents this Relation with the given updates applied to all rows.

Default Implementation
Declaration
Swift

func withUpdate(_ newValues: Row) -> Relation

Observation


                    
                    
                    addAsyncObserver(_:)

Extension method

Undocumented

Declaration

Swift

func addAsyncObserver(_ observer: AsyncRelationChangeObserver) -> AsyncManager.ObservationRemover


                    
                    
                    addAsyncObserver(_:)

Extension method

Undocumented

Declaration

Swift

func addAsyncObserver(_ observer: AsyncRelationChangeCoalescedObserver) -> AsyncManager.ObservationRemover


                    
                    
                    addAsyncObserver(_:)

Extension method

Undocumented

Declaration

Swift

func addAsyncObserver(_ observer: AsyncRelationContentObserver) -> AsyncManager.ObservationRemover

addAsyncObserver(_:postprocessor:) Extension method
If desired, this method can be used to supply a postprocessor function which runs in the background after the rows are accumulated but before results are sent to the observer. This postprocessor can, for example, sort the rows and produce an array which is then passed to the observer.
Declaration
Swift

func addAsyncObserver<T: AsyncRelationContentCoalescedObserver>(_ observer: T, postprocessor: @escaping (Set<Row>) -> T.PostprocessingOutput) -> AsyncManager.ObservationRemover


                    
                    
                    addAsyncObserver(_:)

Extension method

This method may be used when the observer just wants a raw set of rows to be delivered, without any postprocessing.

Declaration

Swift

func addAsyncObserver<T>(_ observer: T) -> AsyncManager.ObservationRemover where T : AsyncRelationContentCoalescedObserver, T.PostprocessingOutput == Set<Row>

Updates

asyncUpdate(_:newValues:) Extension method
Undocumented
Declaration
Swift

func asyncUpdate(_ query: SelectExpression, newValues: Row)

Caching

cache(upTo:) Extension method
Return a new CachingRelation that caches self up to the specified limit
Declaration
Swift

public func cache(upTo: Int) -> CachingRelation

Mutable select


                    
                    
                    mutableSelect(_:)

Extension method

Undocumented

Declaration

Swift

public func mutableSelect(_ expression: SelectExpression) -> MutableSelectRelation

Debugging

setDebugName(_:) Extension method
Set the debug name and return self, for convenient chaining. Value-type relations return a new one rather than mutating in place.
Declaration
Swift

public func setDebugName(_ name: String) -> Self

Asynchronous fetch

asyncBulkRows(_:) Extension method
Fetch rows and invoke a callback as they come in. Each call is passed one or more rows, or an error. If no error occurs, the sequence of calls is terminated by a final call which passes zero rows.
Declaration
Swift

public func asyncBulkRows(_ callback: DispatchContextWrapped<(Result<Set<Row>, RelationError>) -> Void>)
asyncBulkRows(_:) Extension method
Fetch rows and invoke a callback as they come in. Each call is passed one or more rows, or an error. If no error occurs, the sequence of calls is terminated by a final call which passes zero rows.
Declaration
Swift

public func asyncBulkRows(_ callback: @escaping (Result<Set<Row>, RelationError>) -> Void)


                    
                    
                    asyncAllRows(_:)

Extension method

Fetch all rows and invoke a callback when complete.

Declaration

Swift

public func asyncAllRows(_ callback: DispatchContextWrapped<(Result<Set<Row>, RelationError>) -> Void>)

asyncAllRows(_:) Extension method
Fetch all rows and invoke a callback on the current runloop when complete.
Declaration
Swift

public func asyncAllRows(_ callback: @escaping (Result<Set<Row>, RelationError>) -> Void)
asyncAllRows(postprocessor:completion:) Extension method
Fetch all rows and invoke a callback on the current runloop when complete. The postprocessor is run on the background first.
Declaration
Swift

public func asyncAllRows<T>(postprocessor: @escaping (Set<Row>) -> T, completion: @escaping (Result<T, RelationError>) -> Void)

Description

description Extension method
Declaration
Swift

public var description: String { get }

Recursive select


                    
                    
                    recursiveSelect(initialQueryAttr:initialQueryValue:initialValue:rowCallback:filterCallback:completionCallback:)

Extension method

Perform a recursive select query on this relation. This is modeled after cascadingDelete.

Declaration

Swift

public func recursiveSelect<T>(
    initialQueryAttr: Attribute,
    initialQueryValue: RelationValue,
    initialValue: T,
    rowCallback: @escaping (RelationObject, Row, T) -> Result<(T, [RecursiveQuery]), RelationError>,
    filterCallback: @escaping (T, Set<RecursiveQuery>) -> Set<RecursiveQuery>,
    completionCallback: @escaping (Result<T, RelationError>) -> Void)

ArrayProperty creation


                    
                    
                    arrayProperty(idAttr:orderAttr:descending:tag:)

Extension method

Returns an ArrayProperty that gets its data from this relation.

Declaration

Swift

public func arrayProperty(idAttr: Attribute, orderAttr: Attribute, descending: Bool = false, tag: AnyObject? = nil) -> ArrayProperty<RowArrayElement>

Signals

empty Extension method
Returns a Signal that delivers true when the set of rows is empty.
Declaration
Swift

public var empty: Signal<Bool> { get }
nonEmpty Extension method
Returns a Signal that delivers true when the set of rows is non-empty.
Declaration
Swift

public var nonEmpty: Signal<Bool> { get }
allValuesForSingleAttribute(_:) Extension method
Returns a Signal, sourced from this relation, that delivers all values for the single attribute.
Declaration
Swift

public func allValuesForSingleAttribute<V: Hashable>(_ transform: @escaping (RelationValue) -> V?) -> Signal<Set<V>>
allRelationValues() Extension method
Returns a Signal, sourced from this relation, that delivers a set of all RelationValues for the single attribute.
Declaration
Swift

public func allRelationValues() -> Signal<Set<RelationValue>>
allValues(_:) Extension method
Returns a Signal, sourced from this relation, that delivers a set of all transformed values.
Declaration
Swift

public func allValues<V: Hashable>(_ transform: @escaping (Row) -> V?) -> Signal<Set<V>>
allStrings() Extension method
Returns a Signal, sourced from this relation, that delivers a set of all strings for the single attribute.
Declaration
Swift

public func allStrings() -> Signal<Set<String>>
oneRow() Extension method
Returns a Signal, sourced from this relation, that delivers a single row if there is exactly one, otherwise delivers nil.
Declaration
Swift

public func oneRow() -> Signal<Row?>
valueFromOneRow(_:) Extension method
Returns a Signal, sourced from this relation, that delivers a single transformed value if there is exactly one row, otherwise delivers nil.
Declaration
Swift

public func valueFromOneRow<V>(_ transform: @escaping (Row) -> V?) -> Signal<V?>
valueFromOneRow(_:) Extension method
Returns a Signal, sourced from this relation, that delivers a single transformed value if there is exactly one row, otherwise delivers nil.
Declaration
Swift

public func valueFromOneRow<V: Equatable>(_ transform: @escaping (Row) -> V?) -> Signal<V?>
valueFromOneRow(_:orDefault:) Extension method
Returns a Signal, sourced from this relation, that delivers a single transformed value if there is exactly one row, otherwise delivers the given default value.
Declaration
Swift

public func valueFromOneRow<V>(_ transform: @escaping (Row) -> V?, orDefault defaultValue: V) -> Signal<V>
valueFromOneRow(_:orDefault:) Extension method
Returns a Signal, sourced from this relation, that delivers a single transformed value if there is exactly one row, otherwise delivers the given default value.
Declaration
Swift

public func valueFromOneRow<V: Equatable>(_ transform: @escaping (Row) -> V?, orDefault defaultValue: V) -> Signal<V>
oneValueOrNil(_:) Extension method
Returns a Signal, sourced from this relation, that delivers a single transformed value if there is exactly one row, otherwise delivers nil.
Declaration
Swift

public func oneValueOrNil<V>(_ transform: @escaping (RelationValue) -> V?) -> Signal<V?>
oneValueOrNil(_:) Extension method
Returns a Signal, sourced from this relation, that delivers a single transformed value if there is exactly one row, otherwise delivers nil.
Declaration
Swift

public func oneValueOrNil<V: Equatable>(_ transform: @escaping (RelationValue) -> V?) -> Signal<V?>
oneValue(_:orDefault:initialValue:) Extension method
Returns a Signal, sourced from this relation, that delivers a single transformed value if there is exactly one row, otherwise delivers the given default value.
Declaration
Swift

public func oneValue<V>(_ transform: @escaping (RelationValue) -> V?, orDefault defaultValue: V, initialValue: V? = nil) -> Signal<V>
oneValue(_:orDefault:initialValue:) Extension method
Returns a Signal, sourced from this relation, that delivers a single transformed value if there is exactly one row, otherwise delivers the given default value.
Declaration
Swift

public func oneValue<V: Equatable>(_ transform: @escaping (RelationValue) -> V?, orDefault defaultValue: V, initialValue: V? = nil) -> Signal<V>
oneRelationValueOrNil() Extension method
Returns a Signal, sourced from this relation, that delivers a single RelationValue if there is exactly one row, otherwise delivers nil.
Declaration
Swift

public func oneRelationValueOrNil() -> Signal<RelationValue?>
oneStringOrNil(initialValue:) Extension method
Returns a Signal, sourced from this relation, that delivers a single string value if there is exactly one row, otherwise delivers nil.
Declaration
Swift

public func oneStringOrNil(initialValue: String?? = nil) -> Signal<String?>
oneString(initialValue:) Extension method
Returns a Signal, sourced from this relation, that delivers a single string value if there is exactly one row, otherwise delivers an empty string.
Declaration
Swift

public func oneString(initialValue: String? = nil) -> Signal<String>
oneIntegerOrNil(initialValue:) Extension method
Returns a Signal, sourced from this relation, that delivers a single integer value if there is exactly one row, otherwise delivers nil.
Declaration
Swift

public func oneIntegerOrNil(initialValue: Int64?? = nil) -> Signal<Int64?>
oneInteger(initialValue:) Extension method
Returns a Signal, sourced from this relation, that delivers a single integer value if there is exactly one row, otherwise delivers zero.
Declaration
Swift

public func oneInteger(initialValue: Int64? = nil) -> Signal<Int64>
oneDoubleOrNil(initialValue:) Extension method
Returns a Signal, sourced from this relation, that delivers a single double value if there is exactly one row, otherwise delivers nil.
Declaration
Swift

public func oneDoubleOrNil(initialValue: Double?? = nil) -> Signal<Double?>
oneDouble(initialValue:) Extension method
Returns a Signal, sourced from this relation, that delivers a single double value if there is exactly one row, otherwise delivers zero.
Declaration
Swift

public func oneDouble(initialValue: Double? = nil) -> Signal<Double>
oneBoolOrNil(initialValue:) Extension method
Returns a Signal, sourced from this relation, that delivers a single boolean value if there is exactly one row, otherwise delivers nil.
Declaration
Swift

public func oneBoolOrNil(initialValue: Bool?? = nil) -> Signal<Bool?>
oneBool(initialValue:) Extension method
Returns a Signal, sourced from this relation, that delivers a single boolean value if there is exactly one row, otherwise delivers false.
Declaration
Swift

public func oneBool(initialValue: Bool? = nil) -> Signal<Bool>
oneBlobOrNil(initialValue:) Extension method
Returns a Signal, sourced from this relation, that delivers a single blob value if there is exactly one row, otherwise delivers nil.
Declaration
Swift

public func oneBlobOrNil(initialValue: [UInt8]?? = nil) -> Signal<[UInt8]?>
oneBlob(initialValue:) Extension method
Returns a Signal, sourced from this relation, that delivers a single blob value if there is exactly one row, otherwise delivers an empty array.
Declaration
Swift

public func oneBlob(initialValue: [UInt8]? = nil) -> Signal<[UInt8]>
commonValue(_:) Extension method
Returns a Signal, sourced from this relation, that delivers a CommonValue that indicates whether there are zero, one, or multiple rows.
Declaration
Swift

public func commonValue<V>(_ transform: @escaping (RelationValue) -> V?) -> Signal<CommonValue<V>>

Extract all values

extractAllValuesForSingleAttribute(from:_:) Extension method
Returns a set of all values for the single attribute, built from one transformed value for each non-error row in the given set.
Declaration
Swift

public func extractAllValuesForSingleAttribute<V: Hashable>(from rows: AnyIterator<Row>, _ transform: @escaping (RelationValue) -> V?) -> Set<V>
extractAllValuesForSingleAttribute(_:) Extension method
Returns a set of all values for the single attribute, built from one transformed value for each non-error row in the relation.
Declaration
Swift

public func extractAllValuesForSingleAttribute<V: Hashable>(_ transform: @escaping (RelationValue) -> V?) -> Set<V>
extractAllRelationValues(from:) Extension method
Returns a set of all RelationValues for the single attribute, built from one RelationValue for each non-error row in the given set.
Declaration
Swift

public func extractAllRelationValues(from rows: AnyIterator<Row>) -> Set<RelationValue>
extractAllRelationValues() Extension method
Returns a set of all RelationValues for the single attribute in the relation.
Declaration
Swift

public func extractAllRelationValues() -> Set<RelationValue>
extractAllValues(from:_:) Extension method
Returns a set of all values, built from one transformed value for each row in the given set.
Declaration
Swift

public func extractAllValues<V: Hashable>(from rows: AnyIterator<Row>, _ transform: @escaping (Row) -> V?) -> Set<V>
extractAllValues(_:) Extension method
Returns a set of all values, built from one transformed value for each non-error row in the relation.
Declaration
Swift

public func extractAllValues<V: Hashable>(_ transform: @escaping (Row) -> V?) -> Set<V>

Extract one row

extractOneRow(_:) Extension method
Returns a single row if there is exactly one row in the given set, otherwise returns nil.
Declaration
Swift

public func extractOneRow(_ rows: AnyIterator<Row>) -> Row?
extractOneRow() Extension method
Returns a single row if there is exactly one row in the relation, otherwise returns nil.
Declaration
Swift

public func extractOneRow() -> Row?

Extract one value

extractValueFromOneRow(_:_:) Extension method
Returns a single transformed value if there is exactly one row in the given set, otherwise returns nil.
Declaration
Swift

public func extractValueFromOneRow<V>(_ rows: AnyIterator<Row>, _ transform: @escaping (Row) -> V?) -> V?
extractValueFromOneRow(_:) Extension method
Returns a single transformed value if there is exactly one row in the relation, otherwise returns nil.
Declaration
Swift

public func extractValueFromOneRow<V>(_ transform: @escaping (Row) -> V?) -> V?
extractValueFromOneRow(_:_:orDefault:) Extension method
Returns a single transformed value if there is exactly one row in the given set, otherwise returns nil.
Declaration
Swift

public func extractValueFromOneRow<V>(_ rows: AnyIterator<Row>, _ transform: @escaping (Row) -> V?, orDefault defaultValue: V) -> V
extractValueFromOneRow(_:orDefault:) Extension method
Returns a single transformed value if there is exactly one row in the relation, otherwise returns the given default value.
Declaration
Swift

public func extractValueFromOneRow<V>(_ transform: @escaping (Row) -> V?, orDefault defaultValue: V) -> V
extractOneValueOrNil(from:_:) Extension method
Returns a single transformed value if there is exactly one row in the given set, otherwise returns nil.
Declaration
Swift

public func extractOneValueOrNil<V>(from rows: AnyIterator<Row>, _ transform: @escaping (RelationValue) -> V?) -> V?
extractOneValueOrNil(_:) Extension method
Returns a single transformed value if there is exactly one row in the relation, otherwise returns nil.
Declaration
Swift

public func extractOneValueOrNil<V>(_ transform: @escaping (RelationValue) -> V?) -> V?
extractOneValue(from:_:orDefault:) Extension method
Returns a single transformed value if there is exactly one row in the given set, otherwise returns the given default value.
Declaration
Swift

public func extractOneValue<V>(from rows: AnyIterator<Row>, _ transform: @escaping (RelationValue) -> V?, orDefault defaultValue: V) -> V
extractOneValue(_:orDefault:) Extension method
Returns a single transformed value if there is exactly one row in the relation, otherwise returns the given default value.
Declaration
Swift

public func extractOneValue<V>(_ transform: @escaping (RelationValue) -> V?, orDefault defaultValue: V) -> V
extractOneRelationValueOrNil(from:) Extension method
Returns a single RelationValue if there is exactly one row in the given set, otherwise returns nil.
Declaration
Swift

public func extractOneRelationValueOrNil(from rows: AnyIterator<Row>) -> RelationValue?
extractOneRelationValueOrNil() Extension method
Returns a single RelationValue if there is exactly one row in the relation, otherwise returns nil.
Declaration
Swift

public func extractOneRelationValueOrNil() -> RelationValue?

Extract one String

extractOneStringOrNil(from:) Extension method
Returns a a single string value if there is exactly one row in the given set, otherwise returns nil.
Declaration
Swift

public func extractOneStringOrNil(from rows: AnyIterator<Row>) -> String?
extractOneStringOrNil() Extension method
Returns a single string value if there is exactly one row in the relation, otherwise returns nil.
Declaration
Swift

public func extractOneStringOrNil() -> String?
extractOneString(from:) Extension method
Returns a single string value if there is exactly one row in the given set, otherwise returns an empty string.
Declaration
Swift

public func extractOneString(from rows: AnyIterator<Row>) -> String
extractOneString() Extension method
Returns a single string value if there is exactly one row in the relation, otherwise returns an empty string.
Declaration
Swift

public func extractOneString() -> String

Extract one Integer

extractOneIntegerOrNil(from:) Extension method
Returns a single integer value if there is exactly one row in the given set, otherwise returns nil.
Declaration
Swift

public func extractOneIntegerOrNil(from rows: AnyIterator<Row>) -> Int64?
extractOneIntegerOrNil() Extension method
Returns a single integer value if there is exactly one row in the relation, otherwise returns nil.
Declaration
Swift

public func extractOneIntegerOrNil() -> Int64?
extractOneInteger(from:) Extension method
Returns a single integer value if there is exactly one row in the given set, otherwise returns zero.
Declaration
Swift

public func extractOneInteger(from rows: AnyIterator<Row>) -> Int64
extractOneInteger() Extension method
Returns a single integer value if there is exactly one row in the relation, otherwise returns zero.
Declaration
Swift

public func extractOneInteger() -> Int64

Extract one Double

extractOneDoubleOrNil(from:) Extension method
Returns a single double value if there is exactly one row in the given set, otherwise returns nil.
Declaration
Swift

public func extractOneDoubleOrNil(from rows: AnyIterator<Row>) -> Double?
extractOneDoubleOrNil() Extension method
Returns a single double value if there is exactly one row in the relation, otherwise returns nil.
Declaration
Swift

public func extractOneDoubleOrNil() -> Double?
extractOneDouble(from:) Extension method
Returns a single double value if there is exactly one row in the given set, otherwise returns zero.
Declaration
Swift

public func extractOneDouble(from rows: AnyIterator<Row>) -> Double
extractOneDouble() Extension method
Returns a single double value if there is exactly one row in the relation, otherwise returns zero.
Declaration
Swift

public func extractOneDouble() -> Double

Extract one Bool

extractOneBoolOrNil(from:) Extension method
Returns a single boolean value if there is exactly one row in the given set, otherwise returns nil.
Declaration
Swift

public func extractOneBoolOrNil(from rows: AnyIterator<Row>) -> Bool?
extractOneBoolOrNil() Extension method
Returns a single boolean value if there is exactly one row in the relation, otherwise returns nil.
Declaration
Swift

public func extractOneBoolOrNil() -> Bool?
extractOneBool(from:) Extension method
Returns a single boolean value if there is exactly one row in the given set, otherwise returns false.
Declaration
Swift

public func extractOneBool(from rows: AnyIterator<Row>) -> Bool
extractOneBool() Extension method
Returns a single boolean value if there is exactly one row in the relation, otherwise returns false.
Declaration
Swift

public func extractOneBool() -> Bool

Extract one Blob

extractOneBlobOrNil(from:) Extension method
Returns a single blob value if there is exactly one row in the given set, otherwise returns nil.
Declaration
Swift

public func extractOneBlobOrNil(from rows: AnyIterator<Row>) -> [UInt8]?
extractOneBlobOrNil() Extension method
Returns a single blob value if there is exactly one row in the relation, otherwise returns nil.
Declaration
Swift

public func extractOneBlobOrNil() -> [UInt8]?
extractOneBlob(from:) Extension method
Returns a single blob value if there is exactly one row in the given set, otherwise returns an empty array.
Declaration
Swift

public func extractOneBlob(from rows: AnyIterator<Row>) -> [UInt8]
extractOneBlob() Extension method
Returns a single blob value if there is exactly one row in the relation, otherwise returns an empty array.
Declaration
Swift

public func extractOneBlob() -> [UInt8]

Extract CommonValue

extractCommonValue(from:_:) Extension method
Returns a CommonValue that indicates whether there are zero, one, or multiple rows in the given set.
Declaration
Swift

public func extractCommonValue<V>(from rows: AnyIterator<Row>, _ transform: (RelationValue) -> V?) -> CommonValue<V> where V : Equatable
extractCommonValue(_:) Extension method
Returns a CommonValue that indicates whether there are zero, one, or multiple rows in the given set.
Declaration
Swift

public func extractCommonValue<V>(_ transform: (RelationValue) -> V?) -> CommonValue<V> where V : Equatable
okRows() Extension method
MARK: Row iterators Generates all non-error rows in the relation.
Declaration
Swift

public func okRows() -> AnyIterator<Row>

Asynchronous updates

asyncUpdateValue(_:) Extension method
Performs an asynchronous update using a single RelationValue.
Declaration
Swift

public func asyncUpdateValue(_ value: RelationValue)
asyncUpdateString(_:) Extension method
Performs an asynchronous update using a single string value.
Declaration
Swift

public func asyncUpdateString(_ value: String)
asyncUpdateNullableString(_:) Extension method
Performs an asynchronous update using a single optional string value.
Declaration
Swift

public func asyncUpdateNullableString(_ value: String?)
asyncUpdateInteger(_:) Extension method
Performs an asynchronous update using a single integer value.
Declaration
Swift

public func asyncUpdateInteger(_ value: Int64)
asyncUpdateBoolean(_:) Extension method
Performs an asynchronous update using a single boolean value (converted to 0 for false and 1 for true).
Declaration
Swift

public func asyncUpdateBoolean(_ value: Bool)

Signal creation


                    
                    
                    signal(initialValue:_:)

Extension method

Returns a Signal whose values are derived from this relation.

Declaration

Swift

public func signal<T>(initialValue: T?, _ rowsToValue: @escaping (Relation, AnyIterator<Row>) -> T) -> Signal<T>


                    
                    
                    signal(initialValue:_:)

Extension method

Returns a Signal whose values are derived from this relation.

Declaration

Swift

public func signal<T: Equatable>(initialValue: T?, _ rowsToValue: @escaping (Relation, AnyIterator<Row>) -> T) -> Signal<T>


                    
                    
                    signal(initialValue:_:)

Extension method

Returns a Signal whose values are derived from this relation.

Declaration

Swift

public func signal<T>(initialValue: T??, _ rowsToValue: @escaping (Relation, AnyIterator<Row>) -> T?) -> Signal<T?>


                    
                    
                    signal(initialValue:_:)

Extension method

Returns a Signal whose values are derived from this relation.

Declaration

Swift

public func signal<T: Equatable>(initialValue: T??, _ rowsToValue: @escaping (Relation, AnyIterator<Row>) -> T?) -> Signal<T?>

Returns an AsyncReadWriteProperty that delivers a single value (transformed from a string) and updates the relation with a new string (transformed from a value of type T) when one is provided to the property.

Declaration

Swift

public func undoableTransformedString<T>(_ db: UndoableDatabase,
                                         _ action: String, initialValue: String? = nil,
                                         fromString: @escaping (String) -> T,
                                         toString: @escaping (T) -> String) -> AsyncReadWriteProperty<T>