public List <PrecipitationRecord> Process()
{
if (!File.Exists(filename))
{
throw new FileNotFoundException(filename);
}
//Clear database if it already exists
using (JBADbContext db = new JBADbContext(filename))
{
db.Database.EnsureDeleted();
db.Database.EnsureCreated();
db.SaveChanges();
}
using (StreamReader file =
new StreamReader(filename))
{
if (TryReadHeader(file))
{
ParseRecords(file);
return(recordsToAdd);
}
throw new ParseException("Unable to read file header.");
}
}
private static void WriteRecords(List <PrecipitationRecord> records, bool rawSql, string filename)
{
if (rawSql)
{
//need to manually increment ids since EF is not used
int idCounter = 0;
//batch inserts in chunks to avoid massive query size
using (JBADbContext context = new JBADbContext(filename))
{
context.ChangeTracker.AutoDetectChangesEnabled = false;
for (int i = 0; i < Math.Ceiling((double)records.Count / 10000); i++)
{
StringBuilder builder = new StringBuilder("INSERT INTO \"PrecipitationRecords\" VALUES ");
//safe to append values directly as the were parsed into primitives previously
builder.AppendJoin(",", records.Skip(10000 * i).Take(10000).Select(
x =>
$"({idCounter++}, {x.Xref}, {x.Yref}, \"{x.Date:yyyy-MM-dd HH:mm:ss}\", {x.Value})"));
context.Database.ExecuteSqlCommand(builder.ToString());
Console.WriteLine(
$"Inserted {idCounter} records into database for {filename}");
}
context.SaveChanges();
}
}
else
{
//insert using EFCore, slower as each record is inserted individually so requires a round trip
using (JBADbContext context = new JBADbContext(filename))
{
//batch adding to provide status updates
for (int i = 0; i < Math.Ceiling((double)records.Count / 1000); i++)
{
context.ChangeTracker.AutoDetectChangesEnabled = false;
List <PrecipitationRecord> recordsToInsert = records.Skip(1000 * i).Take(1000).ToList();
context.AddRange(recordsToInsert);
context.SaveChanges();
Console.WriteLine(
$"Inserted {i * 1000 + recordsToInsert.Count} records into database for {filename}");
}
}
}
}