More work on relationships.
This commit is contained in:
Brent Simmons
parent
7f5277f3e0
commit
a4b27075a7
@ -8,7 +8,7 @@
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import Foundation
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public protocol DatabaseTable {
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public protocol DatabaseTable: class {
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var name: String {get}
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@ -12,32 +12,82 @@ import Foundation
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// Example: CREATE TABLE if not EXISTS authorLookup (authorID TEXT NOT NULL, articleID TEXT NOT NULL, PRIMARY KEY(authorID, articleID));
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// authorID is primaryKey; articleID is foreignKey.
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public final class DatabaseLookupTable {
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public let name: String
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let primaryKey: String
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let foreignKey: String
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private let name: String
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private let primaryKey: String
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private let foreignKey: String
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private let relationshipName: String
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private weak var relatedTable: DatabaseTable?
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private var foreignIDsWithNoRelationship = Set<String>()
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private var cache = LookupTable(Set<LookupValue>())
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public init(name: String, primaryKey: String, foreignKey: String) {
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public init(name: String, primaryKey: String, foreignKey: String, relatedTable: DatabaseTable, relationshipName: String) {
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self.name = name
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self.primaryKey = primaryKey
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self.foreignKey = foreignKey
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self.relatedTable = relatedTable
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self.relationshipName = relationshipName
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}
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public func fetchLookupTable(_ foreignIDs: Set<String>, _ database: FMDatabase) -> LookupTable? {
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public func attachRelationships(to objects: [DatabaseObject], database: FMDatabase) {
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guard !objects.isEmpty, let lookupTable = fetchLookupTable(objects.databaseIDs(), database) else {
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return;
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}
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attachRelationshipsUsingLookupTable(to: objects, lookupTable: lookupTable, database: database)
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}
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public func saveRelationships(for objects: [DatabaseObject], relationshipName: String, database: FMDatabase) {
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}
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public func removeRelationships(for objects: [DatabaseObject], relationshipName: String, database: FMDatabase) {
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removeLookupsForForeignIDs(objects.databaseIDs(), database)
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}
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}
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private extension DatabaseLookupTable {
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func attachRelationshipsUsingLookupTable(to objects: [DatabaseObject], lookupTable: LookupTable, database: FMDatabase) {
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let primaryIDs = lookupTable.primaryIDs()
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if (primaryIDs.isEmpty) {
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return
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}
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guard let relatedObjects: [DatabaseObject] = relatedTable?.fetchObjectsWithIDs(primaryIDs, database), !relatedObjects.isEmpty else {
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return
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}
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let relatedObjectsDictionary = relatedObjects.dictionary()
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for object in objects {
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let identifier = object.databaseID
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if let lookupValues = lookupTable[identifier], !lookupValues.isEmpty {
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let primaryIDs = lookupValues.primaryIDs()
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let oneObjectRelatedObjects = primaryIDs.flatMap{ (primaryID) -> DatabaseObject? in
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return relatedObjectsDictionary[primaryID]
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}
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object.setRelatedObjects(oneObjectRelatedObjects, name: relationshipName)
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}
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}
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}
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func fetchLookupTable(_ foreignIDs: Set<String>, _ database: FMDatabase) -> LookupTable? {
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let foreignIDsToLookup = foreignIDs.subtracting(foreignIDsWithNoRelationship)
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if foreignIDsToLookup.isEmpty {
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return nil
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}
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var lookupValues = Set<LookupValue>()
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var foreignIDsToFetchFromDatabase = Set<String>()
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// Pull from cache.
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for foreignID in foreignIDsToLookup {
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if let cachedLookups = cache[foreignID] {
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@ -47,111 +97,24 @@ public final class DatabaseLookupTable {
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foreignIDsToFetchFromDatabase.insert(foreignID)
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}
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}
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// Fetch from database.
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if let fetchedLookupValues = fetchLookupValues(foreignIDsToFetchFromDatabase, database) {
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let fetchedLookupValues = fetchLookupValues(foreignIDsToFetchFromDatabase, database)
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if let fetchedLookupValues = fetchedLookupValues {
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lookupValues.formUnion(fetchedLookupValues)
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cache.addLookupValues(fetchedLookupValues)
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}
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// Maintain cache.
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cacheNotFoundForeignIDs(lookupValues, foreignIDsToFetchFromDatabase)
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cache.addLookupValues(fetchedLookupValues)
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return LookupTable(lookupValues: lookupValues)
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}
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public func attachRelationships(to objects: [DatabaseObject], table: DatabaseTable, lookupTableDictionary: LookupTableDictionary, relationshipName: String, database: FMDatabase) {
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let primaryIDs = primaryIDsInLookupTableDictionary(lookupTableDictionary)
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if (primaryIDs.isEmpty) {
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return
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}
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let relatedObjects: [DatabaseObject] = table.fetchObjectsWithIDs(primaryIDs, database)
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if relatedObjects.isEmpty {
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return
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}
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let relatedObjectsDictionary = relatedObjects.dictionary()
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for object in objects {
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let identifier = object.databaseID
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if let lookupValues = lookupTableDictionary[identifier], !lookupValues.isEmpty {
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let primaryIDs = lookupValues.primaryIDs()
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let oneObjectRelatedObjects = primaryIDs.flatMap{ (primaryID) -> DatabaseObject? in
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return relatedObjectsDictionary[primaryID]
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}
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object.attachRelationshipWithObjects(oneObjectRelatedObjects, name: relationshipName)
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}
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}
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}
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func primaryIDsInLookupTableDictionary(_ lookupTableDictionary: LookupTableDictionary) -> Set<String> {
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var primaryIDs = Set<String>()
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for (_, lookupValues) in lookupTableDictionary {
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primaryIDs.formUnion(lookupValues.primaryIDs())
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}
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return primaryIDs
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}
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public func removeLookupsForForeignIDs(_ foreignIDs: Set<String>, _ database: FMDatabase) {
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let foreignIDsToRemove = foreignIDs.subtracting(foreignIDsWithNoRelationship)
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if foreignIDsToRemove.isEmpty {
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return
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}
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for oneForeignID in foreignIDsToRemove {
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cache[oneForeignID] = nil
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}
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foreignIDsWithNoRelationship.formUnion(foreignIDsToRemove)
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database.rs_deleteRowsWhereKey(foreignKey, inValues: Array(foreignIDsToRemove), tableName: name)
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}
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}
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private extension DatabaseLookupTable {
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func fetchLookupValues(_ foreignIDs: Set<String>, _ database: FMDatabase) -> Set<LookupValue>? {
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guard !foreignIDs.isEmpty, let resultSet = database.rs_selectRowsWhereKey(foreignKey, inValues: Array(foreignIDsToLookup), tableName: name) else {
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return nil
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}
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return lookupValuesWithResultSet(resultSet)
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}
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func addToLookupTableDictionary(_ lookupValues: Set<LookupValue>, _ table: inout LookupTableDictionary) {
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for lookupValue in lookupValues {
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let foreignID = lookupValue.foreignID
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if table[foreignID] == nil {
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table[foreignID] = Set([lookupValue])
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}
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else {
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table[foreignID]!.insert(lookupValue)
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}
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}
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}
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func lookupTableDictionary(with lookupValues: Set<LookupValue>) -> LookupTableDictionary {
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var d = LookupTableDictionary()
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addToLookupTableDictionary(lookupValues, &d)
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return d
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}
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func cacheLookupValues(_ lookupValues: Set<LookupValue>) {
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addToLookupTableDictionary(lookupValues, &lookupsByForeignID)
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return LookupTable(lookupValues)
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}
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func cacheNotFoundForeignIDs(_ lookupValues: Set<LookupValue>, _ foreignIDs: Set<String>) {
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// Note where nothing was found, and cache the foreignID in foreignIDsWithNoRelationship.
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let foundForeignIDs = lookupValues.foreignIDs()
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var foreignIDsToRemove = Set<String>()
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for foreignID in foreignIDs {
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@ -163,7 +126,28 @@ private extension DatabaseLookupTable {
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cache.removeLookupValuesForForeignIDs(foreignIDsToRemove)
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}
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func removeLookupsForForeignIDs(_ foreignIDs: Set<String>, _ database: FMDatabase) {
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let foreignIDsToRemove = foreignIDs.subtracting(foreignIDsWithNoRelationship)
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if foreignIDsToRemove.isEmpty {
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return
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}
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cache.removeLookupValuesForForeignIDs(foreignIDsToRemove)
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foreignIDsWithNoRelationship.formUnion(foreignIDsToRemove)
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database.rs_deleteRowsWhereKey(foreignKey, inValues: Array(foreignIDsToRemove), tableName: name)
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}
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func fetchLookupValues(_ foreignIDs: Set<String>, _ database: FMDatabase) -> Set<LookupValue>? {
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guard !foreignIDs.isEmpty, let resultSet = database.rs_selectRowsWhereKey(foreignKey, inValues: Array(foreignIDs), tableName: name) else {
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return nil
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}
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return lookupValuesWithResultSet(resultSet)
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}
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func lookupValuesWithResultSet(_ resultSet: FMResultSet) -> Set<LookupValue> {
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return resultSet.mapToSet(lookupValueWithRow)
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@ -182,42 +166,26 @@ private extension DatabaseLookupTable {
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}
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final class LookupTable {
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private class LookupTable {
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var lookupValues: Set<LookupValue>
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var dictionary = [String: Set<LookupValues>]()
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var dictionary = [String: Set<LookupValue>]()
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init(lookupValues: Set<LookupValue>) {
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init(_ lookupValues: Set<LookupValue>) {
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self.lookupValues = lookupValues
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addLookupValuesToDictionary()
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addLookupValues(lookupValues)
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}
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func primaryIDs() -> Set<String> {
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return lookupValues.primaryIDs()
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var ids = Set<String>()
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for (_, lookupValues) in dictionary {
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ids.formUnion(lookupValues.primaryIDs())
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}
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return ids
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}
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func addLookupValues(_ values: Set<LookupValue>) {
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lookupValues.formUnion(values)
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addLookupValuesToDictionary(values)
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}
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func removeLookupValuesForForeignIDs(_ foreignIDs: Set<String>) {
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for foreignID in foreignIDs {
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self[foreignID] = nil
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}
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let lookupValuesToRemove = lookupValues.filter { (lookupValue) -> Bool in
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foreignIDs.contains(lookupValue.foreignID)
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}
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lookupValues.subtract(lookupValuesToRemove)
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}
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func addLookupValuesToDictionary(_ values: Set<LookupValue>) {
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for lookupValue in values {
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let foreignID = lookupValue.foreignID
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if self[foreignID] == nil {
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@ -229,6 +197,13 @@ final class LookupTable {
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}
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}
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func removeLookupValuesForForeignIDs(_ foreignIDs: Set<String>) {
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for foreignID in foreignIDs {
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self[foreignID] = nil
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}
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}
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subscript(_ foreignID: String) -> Set<LookupValue>? {
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get {
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return dictionary[foreignID]
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@ -239,7 +214,7 @@ final class LookupTable {
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}
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}
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struct LookupValue: Hashable {
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private struct LookupValue: Hashable {
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let primaryID: String
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let foreignID: String
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@ -12,7 +12,8 @@ public protocol DatabaseObject {
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var databaseID: String { get }
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func attachRelationshipWithObjects(_ objects: [DatabaseObject], name: String)
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func setRelatedObjects(_ objects: [DatabaseObject], name: String)
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func relatedObjectsWithName(_ name: String) -> [DatabaseObject]?
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}
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extension Array where Element == DatabaseObject {
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@ -25,4 +26,9 @@ extension Array where Element == DatabaseObject {
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}
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return d
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}
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func databaseIDs() -> Set<String> {
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return Set(self.map { $0.databaseID })
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}
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}
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