Change the way we count changes in order to support INSTEAD OF triggers

Database.changesCount calls sqlite3_changes(), whose documentation says:

> https://sqlite.org/c3ref/changes.html
> Changes to a view that are intercepted by INSTEAD OF triggers are not counted.

Since we want to support INSTEAD OF triggers well, so that record types can be based on views, we switch to sqlite3_total_changes().

Author: groue

GRDB/QueryInterface/Request/QueryInterfaceRequest.swift

@@ -635,8 +635,9 @@ extension QueryInterfaceRequest {
     @discardableResult
     public func deleteAll(_ db: Database) throws -> Int {
         let statement = try SQLQueryGenerator(relation: relation).makeDeleteStatement(db)
+        let prevCount = db.totalChangesCount
         try statement.execute()
-        return db.changesCount
+        return db.totalChangesCount - prevCount
     }
 }
 
@@ -1135,8 +1136,9 @@ extension QueryInterfaceRequest {
             // database not hit
             return 0
         }
+        let prevCount = db.totalChangesCount
         try updateStatement.execute()
-        return db.changesCount
+        return db.totalChangesCount - prevCount
     }
 
     /// Updates matching rows, and returns the number of updated rows.

GRDB/Record/MutablePersistableRecord+Delete.swift

@@ -53,7 +53,8 @@ extension MutablePersistableRecord {
             // Nil primary key
             return false
         }
+        let prevCount = db.totalChangesCount
         try statement.execute()
-        return db.changesCount > 0
+        return (db.totalChangesCount - prevCount) > 0
     }
 }

GRDB/Record/MutablePersistableRecord+Update.swift

@@ -956,8 +956,10 @@ extension MutablePersistableRecord {
             // Nil primary key
             try dao.recordNotFound()
         }
+        let prevCount = db.totalChangesCount
         let returned = try fetch(statement)
-        if db.changesCount == 0 {
+        let changesCount = db.totalChangesCount - prevCount
+        if changesCount == 0 {
             // No row was updated
             try dao.recordNotFound()
         }