Create the income and asset tables.

lib/db.dart

@@ -24,21 +24,45 @@ class DatabaseHelper {
     String path = join(documentsDirectory.path, "com_hyperling_expense.db");
     return await openDatabase(
       path,
-      version: 1,
+      version: 2,
       onCreate: _onCreate,
+      onUpgrade: _onUpgrade,
     );
   }
 
   Future _onCreate(Database db, int version) async {
     await db.execute("""
-        CREATE TABLE expense
+      CREATE TABLE expense
+        ( id INTEGER PRIMARY KEY
+        , name TEXT NOT NULL UNIQUE
+        , cost DOUBLE NOT NULL
+        , frequency TEXT NOT NULL
+        , description TEXT
+      )
+      """);
+  }
+
+  Future _onUpgrade(Database db, int previousVersion, int newVersion) async {
+    // Added in DB version 2.
+    if (previousVersion < 2 && newVersion >= 2) {
+      await db.execute("""
+        CREATE TABLE income
           ( id INTEGER PRIMARY KEY
           , name TEXT NOT NULL UNIQUE
-          , cost DOUBLE NOT NULL
+          , revenue DOUBLE NOT NULL
           , frequency TEXT NOT NULL
           , description TEXT
         )
         """);
+      await db.execute("""
+        CREATE TABLE asset
+          ( id INTEGER PRIMARY KEY
+          , name TEXT NOT NULL UNIQUE
+          , amount DOUBLE NOT NULL
+          , description TEXT
+        )
+        """);
+    }
   }
 
   /// Expense Section
@@ -81,8 +105,11 @@ class DatabaseHelper {
 
   Future<bool> checkExpenseNameExists(String name) async {
     Database db = await instance.db;
-    var expenses = await db.query("expense",
-        where: "name = ?", whereArgs: [name],);
+    var expenses = await db.query(
+      "expense",
+      where: "name = ?",
+      whereArgs: [name],
+    );
     return expenses.isNotEmpty;
   }