added backend code for gas records.

External/Implementations/GasRecordDataAccess.cs

@@ -0,0 +1,47 @@
+using CarCareTracker.External.Interfaces;
+using CarCareTracker.Models;
+using LiteDB;
+
+namespace CarCareTracker.External.Implementations
+{
+    public class GasRecordDataAccess: IGasRecordDataAccess
+    {
+        private static string dbName = "cartracker.db";
+        private static string tableName = "gasrecords";
+        public List<GasRecord> GetGasRecordsByVehicleId(int vehicleId)
+        {
+            using (var db = new LiteDatabase(dbName))
+            {
+                var table = db.GetCollection<GasRecord>(tableName);
+                var gasRecords = table.Find(Query.EQ(nameof(GasRecord.VehicleId), vehicleId)).OrderBy(x => x.Date);
+                return gasRecords.ToList() ?? new List<GasRecord>();
+            };
+        }
+        public GasRecord GetGasRecordById(int gasRecordId)
+        {
+            using (var db = new LiteDatabase(dbName))
+            {
+                var table = db.GetCollection<GasRecord>(tableName);
+                return table.FindById(gasRecordId);
+            };
+        }
+        public bool DeleteGasRecordById(int gasRecordId)
+        {
+            using (var db = new LiteDatabase(dbName))
+            {
+                var table = db.GetCollection<GasRecord>(tableName);
+                table.Delete(gasRecordId);
+                return true;
+            };
+        }
+        public bool SaveGasRecordToVehicle(GasRecord gasRecord)
+        {
+            using (var db = new LiteDatabase(dbName))
+            {
+                var table = db.GetCollection<GasRecord>(tableName);
+                table.Upsert(gasRecord);
+                return true;
+            };
+        }
+    }
+}