public void GenerateDifference(IDataReader source, IDataReader target, Table table, IDataWriter dataWriter, JobSettings settings)
{
if (source.FieldCount != target.FieldCount)
{
throw new MismatchedSchemaException($"Schema difference detected while importing {table.BasicName}. Please ensure the schemas match before syncing");
}
List <object> sourceRecord = ReadRecord(source);
List <object> targetRecord = ReadRecord(target);
List <object> targetsToDelete = new List <object>();
List <List <object> > recordsToInsert = new List <List <object> >();
List <List <object> > recordsToUpdate = new List <List <object> >();
while (true)
{
int?comparison;
if (sourceRecord == null && targetRecord == null)
{
break;
}
else if (sourceRecord == null)
{
comparison = 1;
}
else if (targetRecord == null)
{
comparison = -1;
}
else
{
comparison = CompareObjects(source[table.PrimaryKey], target[table.PrimaryKey]);
}
if (sourceRecord != null)
{
dataWriter.Entry(SerializeRecordAsDictionary(sourceRecord, table));
}
if (comparison == null)
{
throw new NotSupportedKeyException($"Could not compare key {table.PrimaryKey} of {table.Name}. DbSync does not support comparison of keys of it's type");
}
bool consumeTarget = false;
bool consumeSource = false;
//record exists in both
if (comparison == 0)
{
var identical = true;
for (int i = 0; i < sourceRecord.Count; i++)
{
if (!table.Fields[i].IsAuditingColumn)
{
if (CompareObjects(sourceRecord[i], targetRecord[i]) != 0)
{
identical = false;
}
}
}
if (!identical)
{
dataWriter.Update(SerializeRecordAsDictionary(sourceRecord, table));
}
consumeSource = true;
consumeTarget = true;
}
//target contains a record not in source
else if (comparison == 1)
{
if ((table.MergeStrategy ?? settings.MergeStrategy) != Merge.Strategy.Override)
{
dataWriter.Delete(target[table.PrimaryKey]);
}
consumeTarget = true;
}
//source contains a record not in target
else if (comparison == -1)
{
dataWriter.Add(SerializeRecordAsDictionary(sourceRecord, table));
consumeSource = true;
}
if (consumeSource)
{
sourceRecord = ReadRecord(source);
}
if (consumeTarget)
{
targetRecord = ReadRecord(target);
}
}
}