@@ -41,34 +41,93 @@ final class DAO<Record: MutablePersistableRecord> {
4141
4242 func upsertStatement(
4343 _ db: Database ,
44- conflictTarget conflictTargetColumns: [ String ] ,
44+ onConflict conflictTargetColumns: [ String ] ,
45+ doUpdate assignments: ( ( _ excluded: TableAlias ) -> [ ColumnAssignment ] ) ? ,
46+ updateCondition: ( ( _ existing: TableAlias , _ excluded: TableAlias ) -> any SQLExpressible ) ? = nil ,
4547 returning selection: [ any SQLSelectable ] )
4648 throws -> Statement
4749 {
48- // Don't update columns not present in the persistenceContainer
49- // Don't update columns not present in conflictTargetColumns
50- // Don't update primary key columns
51- let lowercaseUpdatedColumns = Set ( persistenceContainer . columns . map { $0 . lowercased ( ) } )
52- . subtracting ( primaryKey . columns . map { $0 . lowercased ( ) } )
53- . subtracting ( conflictTargetColumns . map { $0 . lowercased ( ) } )
54-
55- var updatedColumns : [ String ] = [ ]
50+ // INSERT
51+ let insertedColumns = persistenceContainer . columns
52+ let columnsSQL = insertedColumns . map ( \ . quotedDatabaseIdentifier ) . joined ( separator : " , " )
53+ let valuesSQL = databaseQuestionMarks ( count : insertedColumns . count )
54+ var sql = """
55+ INSERT INTO \( databaseTableName . quotedDatabaseIdentifier ) ( \( columnsSQL ) ) \
56+ VALUES ( \( valuesSQL ) )
57+ """
5658 var arguments = StatementArguments ( persistenceContainer. values)
59+
60+ // ON CONFLICT
61+ if conflictTargetColumns. isEmpty {
62+ sql += " ON CONFLICT "
63+ } else {
64+ let targetSQL = conflictTargetColumns
65+ . map { $0. quotedDatabaseIdentifier }
66+ . joined ( separator: " , " )
67+ sql += " ON CONFLICT( \( targetSQL) ) "
68+ }
69+
70+ // DO UPDATE SET
71+ // We update explicit assignments from the `assignments` parameter.
72+ // Other columns are overwritten by inserted values. This makes sure
73+ // that no information stored in the record is lost, unless explicitly
74+ // requested by the user.
75+ sql += " DO UPDATE SET "
76+ let excluded = TableAlias ( name: " excluded " )
77+ var assignments = assignments ? ( excluded) ?? [ ]
78+ let lowercaseExcludedColumns = Set ( primaryKey. columns. map { $0. lowercased ( ) } )
79+ . union ( conflictTargetColumns. map { $0. lowercased ( ) } )
5780 for column in persistenceContainer. columns {
58- if lowercaseUpdatedColumns. contains ( column. lowercased ( ) ) {
59- updatedColumns. append ( column)
60- arguments += [ persistenceContainer. databaseValue ( at: column) ]
81+ let lowercasedColumn = column. lowercased ( )
82+ if lowercaseExcludedColumns. contains ( lowercasedColumn) {
83+ // excluded (primary key or conflict target)
84+ continue
85+ }
86+ if assignments. contains ( where: { $0. columnName. lowercased ( ) == lowercasedColumn } ) {
87+ // already updated from the `assignments` argument
88+ continue
6189 }
90+ // overwrite
91+ assignments. append ( Column ( column) . set ( to: excluded [ column] ) )
92+ }
93+ let context = SQLGenerationContext ( db)
94+ let updateSQL = try
95+ . compactMap { try . sql ( context) }
96+ . joined ( separator: " , " )
97+ if updateSQL. isEmpty {
98+ if !selection. isEmpty {
99+ // User has asked that no column was overwritten or updated.
100+ // In case of conflict, the upsert would do nothing, and return
101+ // nothing: <https://sqlite.org/forum/forumpost/1ead75e2c45de9a5>.
102+ //
103+ // But we have a RETURNING clause, so we WANT values to be
104+ // returned, and we MUST prevent the upsert statement from
105+ // return nothing. The RETURNING clause is how, for example, we
106+ // fetch the rowid of the upserted record, and feed record
107+ // callbacks such as `didInsert`. Not returning any value would
108+ // be a GRDB bug.
109+ //
110+ // So let's make SURE something is returned, and to do so, let's
111+ // update one column. The first column of the primary key should
112+ // be ok.
113+ let column = primaryKey. columns [ 0 ] . quotedDatabaseIdentifier
114+ sql += " \( column) = \( column) "
115+ }
116+ } else {
117+ sql += updateSQL
118+ arguments += context. arguments
62119 }
63120
64- let query = UpsertQuery (
65- tableName: databaseTableName,
66- insertedColumns: persistenceContainer. columns,
67- conflictTargetColumns: conflictTargetColumns,
68- updatedColumns: updatedColumns)
121+ // WHERE
122+ let existing = TableAlias ( name: databaseTableName)
123+ if let condition = updateCondition ? ( existing, excluded) {
124+ let context = SQLGenerationContext ( db)
125+ sql += try " WHERE " + condition. sqlExpression. sql ( context)
126+ arguments += context. arguments
127+ }
69128
70129 return try makeStatement (
71- sql: query . sql,
130+ sql: sql,
72131 checkedArguments: arguments,
73132 returning: selection)
74133 }
@@ -240,47 +299,6 @@ extension InsertQuery {
240299 }
241300}
242301
243- // MARK: - UpsertQuery
244-
245- private struct UpsertQuery : Hashable {
246- let tableName : String
247- let insertedColumns : [ String ]
248- let conflictTargetColumns : [ String ]
249- let updatedColumns : [ String ]
250- }
251-
252- extension UpsertQuery {
253- @ReadWriteBox private static var sqlCache : [ UpsertQuery : String ] = [ : ]
254- var sql : String {
255- if let sql = Self . sqlCache [ self ] {
256- return sql
257- }
258-
259- let columnsSQL = insertedColumns. map ( \. quotedDatabaseIdentifier) . joined ( separator: " , " )
260- let valuesSQL = databaseQuestionMarks ( count: insertedColumns. count)
261-
262- let onConflictSQL : String
263- if conflictTargetColumns. isEmpty {
264- onConflictSQL = " ON CONFLICT "
265- } else {
266- let targetSQL = conflictTargetColumns
267- . map { $0. quotedDatabaseIdentifier }
268- . joined ( separator: " , " )
269- onConflictSQL = " ON CONFLICT( \( targetSQL) ) "
270- }
271-
272- let updateSQL = updatedColumns. map { " \( $0. quotedDatabaseIdentifier) =? " } . joined ( separator: " , " )
273-
274- let sql = """
275- INSERT INTO \( tableName. quotedDatabaseIdentifier) ( \( columnsSQL) ) \
276- VALUES ( \( valuesSQL) ) \
277- \( onConflictSQL) DO UPDATE SET \( updateSQL)
278- """
279- Self . sqlCache [ self ] = sql
280- return sql
281- }
282- }
283-
284302// MARK: - UpdateQuery
285303
286304private struct UpdateQuery : Hashable {
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