private bool TrivialWhere(DeleteExpression delete, SelectExpression select)
{
if (select.SelectRoles != 0)
{
return(false);
}
if (delete.Where == null)
{
return(false);
}
if (delete.Where.NodeType != ExpressionType.Equal)
{
return(false);
}
var b = (BinaryExpression)delete.Where;
var ce1 = RemoveConvert(b.Left) as ColumnExpression;
var ce2 = RemoveConvert(b.Right) as ColumnExpression;
if (ce1 == null || ce2 == null)
{
return(false);
}
ce1 = ResolveColumn(ce1, select);
ce2 = ResolveColumn(ce2, select);
return(ce1.Name == ce2.Name && ce1.Alias.Equals(ce2.Alias));
}
protected virtual bool CompareDelete(DeleteExpression a, DeleteExpression b)
{
return(a.Table == b.Table &&
a.UseHistoryTable == b.UseHistoryTable &&
Compare(a.Source, b.Source) &&
Compare(a.Where, b.Where));
}
protected internal override Expression VisitDelete(DeleteExpression delete)
{
if (delete.ReturnRowCount == false)
{
return(delete);
}
return(new DeleteExpression(delete.Table, delete.UseHistoryTable, delete.Source, delete.Where, returnRowCount: false));
}
protected internal virtual Expression VisitDelete(DeleteExpression delete)
{
var source = VisitSource(delete.Source);
var where = Visit(delete.Where);
if (source != delete.Source || where != delete.Where)
{
return(new DeleteExpression(delete.Table, delete.UseHistoryTable, (SourceWithAliasExpression)source, where, delete.ReturnRowCount));
}
return(delete);
}
protected internal override Expression VisitDelete(DeleteExpression delete)
{
var where = Visit(delete.Where);
var source = Visit(delete.Source);
if (source != delete.Source || where != delete.Where)
{
return(new DeleteExpression(delete.Table, (SourceWithAliasExpression)source, where));
}
return(delete);
}
protected internal override Expression VisitDelete(DeleteExpression delete)
{
sb.Append("DELETE ");
sb.Append(delete.Name.ToString());
this.AppendNewLine(Indentation.Same);
sb.Append("FROM ");
VisitSource(delete.Source);
if (delete.Where != null)
{
this.AppendNewLine(Indentation.Same);
sb.Append("WHERE ");
Visit(delete.Where);
}
return(delete);
}
protected internal override Expression VisitDelete(DeleteExpression delete)
{
GetColumnCollector(delete.Source.KnownAliases).Visit(delete.Where);
var source = Visit(delete.Source);
var where = Visit(delete.Where);
if (source != delete.Source || where != delete.Where)
{
return(new DeleteExpression(delete.Table, delete.UseHistoryTable, (SourceWithAliasExpression)source, where));
}
return(delete);
}
protected internal override Expression VisitDelete(DeleteExpression delete)
{
var select = (SelectExpression)delete.Source;
if (select.From is not TableExpression table || delete.Table != table.Table)
{
return(delete);
}
if (!TrivialWhere(delete, select))
{
return(delete);
}
return(new DeleteExpression(delete.Table, delete.UseHistoryTable, table, select.Where, delete.ReturnRowCount));
}
protected internal override Expression VisitDelete(DeleteExpression delete)
{
var select = delete.Source as SelectExpression;
TableExpression table = select.From as TableExpression;
if (table == null || delete.Table != table.Table)
{
return(delete);
}
if (!TrivialWhere(delete, select))
{
return(delete);
}
return(new DeleteExpression(delete.Table, table, select.Where));
}