/// <summary>
/// Creates necessary database tables and seeds initial data.
/// </summary>
private async Task InitializeDatabase()
{
using (var context = new MeterReaderContext()) {
DatabaseFacade db = context.Database;
RelationalDatabaseCreator databaseCreator = (RelationalDatabaseCreator)db.GetService <IDatabaseCreator>();
try {
databaseCreator.Create();
}
catch (Exception e) {
// Database already exists
}
try {
databaseCreator.CreateTables();
}
catch (Exception e) {
// Tables already exist
}
using (StreamReader accountsCsv = new StreamReader(CUSTOMER_CSV_FILE_PATH)) {
CustomerAccountCsvParser csvParser = new CustomerAccountCsvParser();
CsvParseResult <CustomerAccount> accounts = await csvParser.ParseCsvFileAsync(accountsCsv);
CustomerAccountDbTableInterface accountsTable = new CustomerAccountDbTableInterface();
await accountsTable.InsertEntriesAsync(accounts.Data);
}
}
}
/// <summary>
/// Asynchronously inserts meter reading data into the database if it is unique otherwise ignores it.
/// </summary>
/// <param name="meterReadings">Meter reading data to insert.</param>
/// <returns>DbResult detailing the result of the insert operation.</returns>
public async Task <DbResult> InsertEntriesAsync(ICollection <MeterReading> meterReadings)
{
using (var context = new MeterReaderContext()) {
IEnumerable <MeterReading> validReadings = RemoveInvalidReadings(meterReadings, context);
try {
foreach (MeterReading reading in validReadings)
{
reading.Id = GenerateMeterReadingId(reading);
}
int initialRowCount = context.MeterReadings.Count();
await context.BulkMergeAsync(validReadings);
int finalRowCount = context.MeterReadings.Count();
int insertCount = finalRowCount - initialRowCount;
return(new DbResult {
InsertCount = insertCount,
ErrorCount = meterReadings.Count - insertCount
});
}
catch (Exception e) {
return(new DbResult {
InsertCount = 0,
ErrorCount = meterReadings.Count
});
}
}
}
/// <summary>
/// Removes all entries from the meter readings table.
/// </summary>
/// <returns>True if all entries were deleted else false.</returns>
public async Task <bool> ClearTableAsync()
{
using (var context = new MeterReaderContext()) {
await context.BulkDeleteAsync(context.MeterReadings);
return(context.MeterReadings.Count() == 0);
}
}
/// <summary>
/// Asynchronously inserts account data into the database if it is unique otherwise ignores it.
/// </summary>
/// <param name="accounts">Account data to insert.</param>
/// <returns>DbResult detailing the result of the insert operation.</returns>
public async Task <DbResult> InsertEntriesAsync(ICollection <CustomerAccount> accounts)
{
using (var context = new MeterReaderContext()) {
int initialRowCount = context.Accounts.Count();
await context.BulkMergeAsync(accounts);
int finalRowCount = context.Accounts.Count();
int insertCount = finalRowCount - initialRowCount;
return(new DbResult {
InsertCount = insertCount,
ErrorCount = accounts.Count - insertCount
});
}
}
/// <summary>
/// Returns the filtered subset of meter readings that have a valid Account ID.
/// </summary>
/// <param name="readings">Meter readings to filter.</param>
/// <returns>Valid meter readings subset.</returns>
private IEnumerable <MeterReading> RemoveInvalidReadings(ICollection <MeterReading> readings, MeterReaderContext context)
{
IEnumerable <string> actualAccountIds = context.Accounts.Select(account => account.Id);
return(readings.Where(reading => actualAccountIds.Contains(reading.AccountId)));
}
