public override SelectExpression Select(IEntityType entityType)
{
if (entityType.HasTemporalTable())
{
var _TemporalTableExpression = new TemporalTableExpression(
entityType.GetTableName(),
entityType.GetSchema(),
entityType.GetTableName().ToLower().Substring(0, 1));
return(base.Select(entityType, _TemporalTableExpression));
}
return(base.Select(entityType));
}
protected virtual Expression VisitTemporalTable(TemporalTableExpression tableExpression)
{
Sql.Append(SqlGenerationHelper.DelimitIdentifier(tableExpression.Name, tableExpression.Schema));
switch (tableExpression.TemporalQueryType)
{
case TemporalQueryType.None:
break;
case TemporalQueryType.AsOf:
{
var _AsOfDate = tableExpression.AsOfDate.Name;
Sql.Append($" FOR SYSTEM_TIME AS OF @{_AsOfDate}");
if (!CommandBuilder.Parameters.Any(x => x.InvariantName == tableExpression.AsOfDate.Name))
{
CommandBuilder.AddParameter(tableExpression.AsOfDate.Name, _AsOfDate);
}
break;
}
case TemporalQueryType.FromTo:
{
var _StartDate = tableExpression.StartDate.Name;
var _EndDate = tableExpression.EndDate.Name;
Sql.Append($" FOR SYSTEM_TIME FROM @{_StartDate} TO @{_EndDate}");
if (!CommandBuilder.Parameters.Any(x => x.InvariantName == _StartDate))
{
CommandBuilder.AddParameter(_StartDate, _StartDate);
}
if (!CommandBuilder.Parameters.Any(x => x.InvariantName == _EndDate))
{
CommandBuilder.AddParameter(_EndDate, _EndDate);
}
break;
}
case TemporalQueryType.BetweenAnd:
{
var _StartDate = tableExpression.StartDate.Name;
var _EndDate = tableExpression.EndDate.Name;
Sql.Append($" FOR SYSTEM_TIME BETWEEN @{_StartDate} AND @{_EndDate}");
if (!CommandBuilder.Parameters.Any(x => x.InvariantName == _StartDate))
{
CommandBuilder.AddParameter(_StartDate, _StartDate);
}
if (!CommandBuilder.Parameters.Any(x => x.InvariantName == _EndDate))
{
CommandBuilder.AddParameter(_EndDate, _EndDate);
}
break;
}
case TemporalQueryType.ContainedIn:
{
var _StartDate = tableExpression.StartDate.Name;
var _EndDate = tableExpression.EndDate.Name;
Sql.Append($" FOR SYSTEM_TIME CONTAINED IN(@{_StartDate}, @{_EndDate})");
if (!CommandBuilder.Parameters.Any(x => x.InvariantName == _StartDate))
{
CommandBuilder.AddParameter(_StartDate, _StartDate);
}
if (!CommandBuilder.Parameters.Any(x => x.InvariantName == _EndDate))
{
CommandBuilder.AddParameter(_EndDate, _EndDate);
}
break;
}
case TemporalQueryType.All:
{
Sql.Append(" FOR SYSTEM_TIME ALL");
break;
}
default:
break;
}
Sql
.Append(AliasSeparator)
.Append(SqlGenerationHelper.DelimitIdentifier(tableExpression.Alias));
return(tableExpression);
}