public unionstatement(selectstatements selects, orderbystatement orderby) : this(false, selects, orderby)
{
}
public unionstatement(bool all, selectstatements selects) : this(all, selects, null)
{
}
public new orderbystatement OrderBy; /* a good example of meaningful shadowing */
public unionstatement(bool all, selectstatements selects, orderbystatement orderby)
{
All = all;
Selects = selects;
OrderBy = orderby;
}
public unionstatement(selectstatements selects) : this(false, selects, null)
{
}
public override ITable[] DependentUpon()
{
List <ITable> result = new List <ITable>();
ITable tab;
/* a view might depend on various tables and other views, too */
selectstatement stmt = ConstituentSelectStatement;
selectstatements sts;
/* [dlatikay 20160913] pass-through views might have their dependencies specified in attributes */
object[] da = Attribute.GetCustomAttributes(this.GetType(), typeof(DependencyAttribute), false);
for (int i = 0; i < da.Length; ++i)
{
var attr = da[i] as DependencyAttribute;
tab = TableobjectFromName(attr.Relation.Name);
if (!result.Contains(tab))
{
result.Add(tab);
}
}
/* decompose possible unions */
var unionStatement = stmt as unionstatement;
if (unionStatement != null)
{
sts = unionStatement.Selects; /* a union might contain multiple selects (at least two) */
}
else
{
sts = new selectstatements()
{
stmt
}
}; /* a singular statement */
/* iterate all of them */
foreach (selectstatement st in sts)
{
/* 1. look in the tables */
if (st.Tables != null)
{
foreach (tableexpression tex in st.Tables)
{
tab = TableobjectFromName(tex.Tablename);
if (!result.Contains(tab))
{
result.Add(tab);
}
}
}
/* 2. look in the joins */
if (st.Joins != null)
{
foreach (joinstatement join in st.Joins)
{
tab = TableobjectFromName(join.Tablename);
if (!result.Contains(tab))
{
result.Add(tab);
}
}
}
/* 3. look in the subqueries that might reside in the where clause */
/* -!- not yet cared to implement */
/* 4. look in the subqueries that might reside in the field list */
/* -!- not yet cared to implement */
}
/* deliver */
return(result.ToArray());
}
ITable TableobjectFromName(string name)
{
try
{
return((ITable)Assembly.GetAssembly(this.GetType()).CreateInstance("dal.schema." + name));
}
catch (Exception)
{
throw new ArgumentOutOfRangeException("name", String.Format("Failed to resolve the name \"{0}\" in the \"dal.schema\" namespace.", name));
}
}
}
