public override string ConstructQuery()
{
//base query
StringBuilder sb = new StringBuilder("SELECT");
//handle top
if (TableMetadata.MaxSaturationItems > 0)
{
sb.AppendFormat(" TOP {0} {1}", TableMetadata.MaxSaturationItems, TableMetadata.Query);
}
else
{
sb.AppendFormat(" {0}", TableMetadata.Query);
}
//mod
sb.AppendFormat(" WHERE {0} % {1} = {2}", TableMetadata.ModField, Bucket.Catalog.ComputeNode.GlobalBucketCount, Bucket.BucketMod);
//base filter
if (!string.IsNullOrWhiteSpace(TableMetadata.Filter))
{
sb.AppendFormat(" AND ({0})", TableMetadata.Filter);
}
//update value
if (this.TableMetadata.SaturationUpdateType == typeof(DateTime))
{
sb.AppendFormat(
" AND {0} {1} '{2} {3}'",
TableMetadata.SaturationUpdateField,
TableMetadata.SaturationUpdateComparator,
((DateTime)LastUpdateValue).ToShortDateString(),
((DateTime)LastUpdateValue).ToShortTimeString());
}
else if (this.TableMetadata.SaturationUpdateType == typeof(string))
{
sb.AppendFormat(
" AND {0} {1} '{2}'",
TableMetadata.SaturationUpdateField,
TableMetadata.SaturationUpdateComparator,
LastUpdateValue.ToString());
}
else
{
sb.AppendFormat(
" AND {0} {1} {2}",
TableMetadata.SaturationUpdateField,
TableMetadata.SaturationUpdateComparator,
LastUpdateValue.ToString());
}
//order by
if (!string.IsNullOrWhiteSpace(TableMetadata.OrderBy))
{
sb.AppendFormat(" ORDER BY {0}", TableMetadata.OrderBy);
}
return(sb.ToString());
}
/// <summary>
/// update the last value
/// </summary>
/// <param name="obj"></param>
/// <returns></returns>
public bool UpdateLastValue(object obj)
{
//check for null
if (obj == null)
{
return(false);
}
//check for init last value
if (LastUpdateValue == null)
{
LastUpdateValue = obj;
return(true);
}
//value was updated
bool bUpdated = false;
try
{
//compare the objects
int comparison = (Convert.ChangeType(obj, LastUpdateValue.GetType()) as IComparable).CompareTo(LastUpdateValue);
//handle update logic
switch (TableMetadata.SaturationUpdateComparator)
{
case Comparators.GREATER_THAN:
if (comparison > 0)
{
LastUpdateValue = obj;
bUpdated = true;
}
break;
case Comparators.GREATER_THAN_EQUAL_TO:
if (comparison >= 0)
{
LastUpdateValue = obj;
bUpdated = true;
}
break;
case Comparators.LESS_THAN:
if (comparison < 0)
{
LastUpdateValue = obj;
bUpdated = true;
}
break;
case Comparators.LESS_THAN_EQUAL_TO:
if (comparison >= 0)
{
LastUpdateValue = obj;
bUpdated = true;
}
break;
}
}
catch (Exception ex)
{
System.Diagnostics.Trace.WriteLine(ex.ToString());
}
return(bUpdated);
}
