public static ProjectedColumns ProjectColumns(
Expression expression,
IEnumerable<ColumnDeclaration> existingColumns,
TableAlias newAlias,
params TableAlias[] existingAliases)
{
return ProjectColumns(expression, existingColumns, newAlias, (IEnumerable<TableAlias>)existingAliases);
}
protected virtual string GetAliasName(TableAlias alias)
{
string name;
if(!this.aliases.TryGetValue(alias, out name))
{
name = "t" + this.aliases.Count;
this.aliases.Add(alias, name);
}
return name;
}
public static ProjectedColumns ProjectColumns(
Expression expression,
IEnumerable<ColumnDeclaration> existingColumns,
TableAlias newAlias,
IEnumerable<TableAlias> existingAliases)
{
ColumnProjector projector = new ColumnProjector(existingColumns, newAlias, existingAliases);
Expression expr = projector.Visit(expression);
return new ProjectedColumns { Projector = expr, Columns = projector.columns };
}
private ColumnProjector(IEnumerable<ColumnDeclaration> existingColumns, TableAlias newAlias, IEnumerable<TableAlias> existingAliases)
{
this.newAlias = newAlias;
this.existingAliases = new HashSet<TableAlias>(existingAliases);
this.map = new Dictionary<ColumnExpression, ColumnExpression>();
if(existingColumns != null)
{
this.columns = new List<ColumnDeclaration>(existingColumns);
}
else
{
this.columns = new List<ColumnDeclaration>();
}
}
private BindResult RebindOrderings(IList<OrderByDeclaration> orderings, TableAlias alias, HashSet<TableAlias> existingAliases, IList<ColumnDeclaration> existingColumns)
{
List<ColumnDeclaration> newColumns = null;
List<OrderByDeclaration> newOrderings = new List<OrderByDeclaration>();
foreach(OrderByDeclaration ordering in orderings)
{
SqlExpression expr = ordering.Expression;
ColumnExpression column = expr as ColumnExpression;
if(column == null || existingAliases != null && existingAliases.Contains(column.TableAlias))
{
int ordinal = 0;
foreach(ColumnDeclaration decl in existingColumns)
{
ColumnExpression declColumn = decl.Expression as ColumnExpression;
if(decl.Expression == ordering.Expression || column != null && declColumn != null && column.TableAlias == declColumn.TableAlias && column.ColumnName == declColumn.ColumnName)
{
expr = new ColumnExpression(alias, decl.DeclaredName);
break;
}
ordinal++;
}
if(expr == ordering.Expression)
{
if(newColumns == null)
{
newColumns = new List<ColumnDeclaration>(existingColumns);
existingColumns = newColumns;
}
string colName = column != null ? column.ColumnName : "c" + ordinal;
colName = GetAvailableColumnName(newColumns, colName);
newColumns.Add(new ColumnDeclaration(colName, ordering.Expression));
expr = new ColumnExpression(alias, colName);
}
newOrderings.Add(new OrderByDeclaration(ordering.OrderType, expr));
}
}
return new BindResult() { Columns = existingColumns, Orderings = newOrderings };
}
public TableExpression(TableAlias tableAlias, string tableName)
: base(SqlExpressionType.Table, tableAlias)
{
this.TableName = tableName;
}
public SelectExpression(
TableAlias tableAlias,
IEnumerable<ColumnDeclaration> columns,
SqlExpression from,
SqlExpression where
)
: this(tableAlias, columns, from, where, null, null)
{
}
public SelectExpression(
TableAlias tableAlias,
IEnumerable<ColumnDeclaration> columns,
SqlExpression from,
SqlExpression where,
IEnumerable<OrderByDeclaration> orderBy,
IEnumerable<SqlExpression> groupBy
)
: this(tableAlias, columns, from, where, orderBy, groupBy, null, null, false)
{
}
public SelectExpression(
TableAlias tableAlias,
IEnumerable<ColumnDeclaration> columns,
SqlExpression from,
SqlExpression where,
IEnumerable<OrderByDeclaration> orderBy,
IEnumerable<SqlExpression> groupBy,
int? skip,
int? take,
bool isDistinct
)
: base(SqlExpressionType.Select, tableAlias)
{
this.Columns = columns.ToReadOnly();
this.From = from;
this.Where = where;
this.OrderBy = orderBy.ToReadOnly();
this.GroupBy = groupBy.ToReadOnly();
this.Skip = skip;
this.Take = take;
this.IsDistinct = isDistinct;
}
public ColumnExpression(TableAlias tableAlias, string columnName)
: base(SqlExpressionType.Column)
{
this.TableAlias = tableAlias;
this.ColumnName = columnName;
}
public AliasedExpression(SqlExpressionType nodeType, TableAlias tableAlias)
: base(nodeType)
{
this.TableAlias = tableAlias;
}