refactored the database part a bunch, now have two tables, session and answer

lib/pages/practice/PracticeAnswer.dart

@@ -6,10 +6,10 @@ import 'package:ohthatsa/util/Months.dart';
 class PracticeAnswer {
   final int question;
   final int answer;
-  final PracticeType practiceType;
   DateTime dateTime;
+  int sessionId = -1;
 
-  PracticeAnswer(this.question, this.answer, this.practiceType){
+  PracticeAnswer(this.question, this.answer){
     dateTime = DateTime.now();
   }
 
@@ -19,8 +19,8 @@ class PracticeAnswer {
     return <String, dynamic>{
       "question": question,
       "answer": answer,
-      "type": practiceType.toString().split(".").last,
-      "time": timeFormat
+      "time": timeFormat,
+      "sessionId": sessionId
     };
   }
 }

lib/pages/practice/PracticeDatabase.dart

@@ -4,47 +4,50 @@ import 'package:sqflite/sqflite.dart';
 import 'package:path/path.dart';
 
 class PracticeDatabase {
-  Database _database;
-
-  static PracticeDatabase getDatabase() {
-    PracticeDatabase practiceDatabase = PracticeDatabase();
-    practiceDatabase.open();
-    return practiceDatabase;
-  }
-
-  _onCreate(Database database, int version) async {
+  static _onCreate(Database database, int version) async {
     String types = PracticeType.values.map((type) => "'${type.toString().split(".").last}'").join(", ");
     await database.execute('''
+    CREATE TABLE PracticeSession (
+      id INTEGER PRIMARY KEY AUTOINCREMENT,
+      type TEXT CHECK( type IN ($types) ) NOT NULL
+    );
+    ''');
+    await database.execute('''
     CREATE TABLE PracticeAnswer (
       id INTEGER PRIMARY KEY AUTOINCREMENT,
+      sessionId INTEGER NOT NULL,
       question INTEGER NOT NULL,
       answer INTEGER NOT NULL,
-      type TEXT CHECK( type IN ($types) ) NOT NULL,
-      time DATETIME NOT NULL
+      time DATETIME NOT NULL,
+      
+      FOREIGN KEY(sessionId) REFERENCES PracticeSession(id)
     );
     ''');
   }
 
-  Future open() async{
+  static Future<Database> getDatabase() async {
     var databasesPath = await getDatabasesPath();
     final databaseName = "answers.db";
-    var path = join(databasesPath, databaseName);
-    this._database = await openDatabase(
-        path,
-        version: 1,
-        onCreate: _onCreate
+
+    return await openDatabase(
+      join(databasesPath, databaseName),
+      version: 1,
+      onCreate: _onCreate
     );
   }
 
-  Future insertAnswer(PracticeAnswer answer) async {
-    this._database.insert("PracticeAnswer", answer.toMap());
-  }
-
-  static insertAnswers(List<PracticeAnswer> answers) async {
-    var practiceDatabase = PracticeDatabase();
-    await practiceDatabase.open();
+  static insertAnswers(List<PracticeAnswer> answers, PracticeType practiceType) async {
+    var db = await getDatabase();
+    int sessionId = await db.insert("PracticeSession",
+        <String, dynamic>{
+          "type": practiceType.toString().split(".").last
+        }
+    );
+    var batch = db.batch();
     answers.forEach((answer) {
-      practiceDatabase.insertAnswer(answer);
+      answer.sessionId = sessionId;
+      batch.insert("PracticeAnswer", answer.toMap());
     });
+    await batch.commit();
   }
 }

lib/pages/practice/PracticePage.dart

@@ -25,6 +25,7 @@ class PracticePage extends StatefulWidget {
 class _PracticeState extends State<PracticePage> {
   int _startCount = 0;
   bool _showCorrect = true;
+  PracticeType practiceType;
   PracticeThing practiceThing;
 
   int _count = 0;
@@ -34,7 +35,8 @@ class _PracticeState extends State<PracticePage> {
   _PracticeState(PracticeSetup practiceSetup){
     this._startCount = practiceSetup.count;
     this._showCorrect = practiceSetup.showCorrect;
-    switch(practiceSetup.practiceType){
+    practiceType = practiceSetup.practiceType;
+    switch(practiceType){
       case (PracticeType.month): {
         this.practiceThing = PracticeThingMonth();
         break;
@@ -213,7 +215,7 @@ class _PracticeState extends State<PracticePage> {
       practiceThing.next()
     });
     if((_startCount - _count) == 0) {
-      PracticeDatabase.insertAnswers(practiceThing.answers);
+      PracticeDatabase.insertAnswers(practiceThing.answers, practiceType);
       showDialog(
         context: context,
         child: finishedPracticeDialog()

lib/pages/practice/PracticeThingCentury.dart

@@ -15,7 +15,7 @@ class PracticeThingCentury extends PracticeThing {
 
   @override
   bool answer(int answer) {
-    answers.add(PracticeAnswer(current, answer, PracticeType.month));
+    answers.add(PracticeAnswer(current, answer));
     final correctAnswer = DayCalculator.getCenturyValue(current);
     return answer == correctAnswer;
   }

lib/pages/practice/PracticeThingLeap.dart

@@ -14,7 +14,7 @@ class PracticeThingLeap extends PracticeThing {
 
   @override
   bool answer(int answer) {
-    answers.add(PracticeAnswer(current, answer, PracticeType.month));
+    answers.add(PracticeAnswer(current, answer));
     final correctAnswer = DayCalculator.isLeapYear(current);
     return (answer != 0) == correctAnswer;
   }

lib/pages/practice/PracticeThingMod.dart

@@ -12,7 +12,7 @@ class PracticeThingMod extends PracticeThing {
 
   @override
   bool answer(int answer) {
-    answers.add(PracticeAnswer(current, answer, PracticeType.mod));
+    answers.add(PracticeAnswer(current, answer));
     final correctAnswer = current % 7;
     return answer == correctAnswer;
   }

lib/pages/practice/PracticeThingMonth.dart

@@ -15,7 +15,7 @@ class PracticeThingMonth extends PracticeThing {
   }
   @override
   bool answer(int answer) {
-    answers.add(PracticeAnswer(current.i, answer, PracticeType.month));
+    answers.add(PracticeAnswer(current.i, answer));
     return current.value == answer;
   }