internal static DatabaseField GetForeignKeyField(TableMetadata parentEntity, TableMetadata childEntity)
{
TableRelation[] relations = parentEntity.Relations;
foreach (TableRelation relation in relations)
{
if (relation is ManyToManyTableRelation)
{
continue;
}
if (relation.RelatedTableName == childEntity.TableName)
{
return(childEntity.GetField(((ParentTableRelation)relation).ForeignKeyName));
}
}
throw new ArgumentException("No relation found between the specified tables");
}
/// <summary>
/// Gets the data from a related table in a ManyToMany relation.
/// </summary>
/// <param name="relatedTableType">Type of the related entity</param>
/// <param name="intermediaryRelatedTableType">Type of the intermediary table</param>
/// <returns>TableMetadata array which contains the results</returns>
protected Array GetRelatedTableData(Type relatedTableType, Type intermediaryRelatedTableType)
{
PersistentObject persistent = null;
ManyToManyTableRelation relation = null;
DataSet ds = null;
try
{
//create a instance of the table so we can check the relations between out table and this
TableMetadata relatedTable = (TableMetadata)Activator.CreateInstance(relatedTableType);
TableMetadata intermediateTable = (TableMetadata)Activator.CreateInstance(intermediaryRelatedTableType);
object primaryKeyValue = GetPrimaryKeyField().fieldValue;
//first check the fieldValue of the primary key
if (GetPrimaryKeyField().fieldValue == null)
{
throw new InvalidOperationException("The primary key does not have a fieldValue");
}
//get the relation
foreach (TableRelation var in Relations)
{
if (var is ManyToManyTableRelation)
{
if (var.RelatedTableName == relatedTable.TableName)
{
relation = (ManyToManyTableRelation)var;
break;
}
}
}
//check if we got the relation
if (relation == null)
{
throw new ArgumentException("A relation cannot be found between the tables");
}
//we have the relation between the 2 tables.
persistent = new PersistentObject(this);
QueryCriteria qcThis = new QueryCriteria(TableName, GetPrimaryKeyField());
qcThis.Add(CriteriaOperator.Equality, GetPrimaryKeyField(), primaryKeyValue);
//generate here the inner join
QueryCriteria qcIntermediaryTable = new QueryCriteria(intermediateTable.TableName, intermediateTable.GetField(relation.IntermediaryKeyFieldFromParentTable));
QueryCriteria qcChild = new QueryCriteria(relatedTable);
qcThis.AddJoin(JoinType.Inner, TableName, GetPrimaryKeyField(), intermediateTable.TableName,
intermediateTable.GetField(relation.IntermediaryKeyFieldFromParentTable), qcIntermediaryTable);
qcThis.AddJoin(JoinType.Inner, intermediateTable.TableName, intermediateTable.GetField(relation.IntermediaryKeyFieldFromChildTable), relatedTable.TableName,
relatedTable.GetField(relation.IntermediaryKeyFieldFromChildTable), qcChild);
ds = persistent.GetDataSet(qcThis);
Array data = Array.CreateInstance(relatedTableType, ds.Tables[0].Rows.Count);
for (int i = 0; i < data.Length; i++)
{
object instance = Activator.CreateInstance(relatedTableType);
data.SetValue(instance, i);
//loop thru dataset
for (int j = START_INDEX_FIELD; j < ds.Tables[0].Columns.Count; j++)
{
Type tp = data.GetValue(i).GetType();
object[] args = new[] { ds.Tables[0].Columns[j].ColumnName, ds.Tables[0].Rows[i][j] };
tp.InvokeMember("SetFieldValue", BindingFlags.InvokeMethod | BindingFlags.Public | BindingFlags.Instance, null, instance, args);
}
}
return(data);
}
catch
{
throw;
}
finally
{
if (ds != null)
{
ds.Dispose();
}
}
}
