private void GenerateGrouping(SelectStatement statement, Grouping grouping)
{
if (grouping == null)
{
return;
}
if (grouping.Keys != null && grouping.Keys.Length > 0)
{
//创建分组子句
statement.GroupBy = new GroupByClause();
foreach (var key in grouping.Keys)
{
var source = statement.From(key.Name, null, out var property);
if (property.IsComplex)
{
throw new DataException($"The grouping key '{property.Name}' can not be a complex property.");
}
statement.GroupBy.Keys.Add(source.CreateField(property));
statement.Select.Members.Add(source.CreateField(property.GetFieldName(out var alias), key.Alias ?? alias));
}
if (grouping.Filter != null)
{
statement.GroupBy.Having = statement.Where(grouping.Filter);
}
}
foreach (var aggregate in grouping.Aggregates)
{
if (string.IsNullOrEmpty(aggregate.Name) || aggregate.Name == "*")
{
statement.Select.Members.Add(
new AggregateExpression(aggregate.Function, Expression.Constant(0))
{
Alias = string.IsNullOrEmpty(aggregate.Alias) ? aggregate.Function.ToString() : aggregate.Alias
});
}
else
{
var source = statement.From(aggregate.Name, null, out var property);
if (property.IsComplex)
{
throw new DataException($"The field '{property.Name}' of aggregate function can not be a complex property.");
}
statement.Select.Members.Add(
new AggregateExpression(aggregate.Function, source.CreateField(property))
{
Alias = string.IsNullOrEmpty(aggregate.Alias) ? aggregate.Name : aggregate.Alias
});
}
}
}
private void GenerateSortings(SelectStatement statement, TableIdentifier origin, Sorting[] sortings)
{
if (sortings == null || sortings.Length == 0)
{
return;
}
statement.OrderBy = new OrderByClause();
foreach (var sorting in sortings)
{
if (string.IsNullOrEmpty(sorting.Name))
{
continue;
}
var source = statement.From(origin, sorting.Name, null, out var property);
var simplex = property.IsSimplex ?
(IDataEntitySimplexProperty)property :
throw new DataException($"The specified '{property.Entity.Name}.{property.Name}' is a composite(navigation) property that is not sortable.");
if (simplex.IsPrimaryKey || simplex.Sortable)
{
statement.OrderBy.Add(source.CreateField(property), sorting.Mode);
}
else
{
throw new DataException($"The specified '{property.Entity.Name}.{property.Name}' property is not sortable and must be enabled for sorting before it can be sorted.");
}
}
}
private void GenerateSortings(SelectStatement statement, TableIdentifier origin, Sorting[] sortings)
{
if (sortings == null || sortings.Length == 0)
{
return;
}
statement.OrderBy = new OrderByClause();
foreach (var sorting in sortings)
{
var source = statement.From(origin, sorting.Name, out var property);
statement.OrderBy.Add(source.CreateField(property), sorting.Mode);
}
}