/// <summary>
/// Returns an existing table or registers the current one
/// </summary>
/// <param name="tableExpression"></param>
/// <param name="builderContext"></param>
/// <returns>A registered table or the current newly registered one</returns>
public virtual TableExpression RegisterTable(TableExpression tableExpression, BuilderContext builderContext)
{
// 1. Find the table in current scope
var foundTableExpression = (from t in builderContext.EnumerateScopeTables()
where t.IsEqualTo(tableExpression)
select t).SingleOrDefault();
if (foundTableExpression != null)
return foundTableExpression;
// 2. Find it in all scopes, and promote it to current scope.
foundTableExpression = PromoteTable(tableExpression, builderContext);
if (foundTableExpression != null)
return foundTableExpression;
// 3. Add it
builderContext.CurrentSelect.Tables.Add(tableExpression);
return tableExpression;
}
/// <summary>
/// Registers an association
/// </summary>
/// <param name="tableExpression">The table holding the member, to become the joinedTable</param>
/// <param name="tableMemberInfo"></param>
/// <param name="builderContext"></param>
/// <returns></returns>
public virtual TableExpression RegisterAssociation(TableExpression tableExpression, MemberInfo tableMemberInfo,
BuilderContext builderContext)
{
IList<MemberInfo> theseKeys, otherKeys;
TableJoinType joinType;
string joinID;
var otherTableType = DataMapper.GetAssociation(tableExpression, tableMemberInfo, out theseKeys, out otherKeys,
out joinType, out joinID, builderContext.QueryContext.DataContext);
// if the memberInfo has no corresponding association, we get a null, that we propagate
if (otherTableType == null)
return null;
// the current table has the foreign key, the other table the referenced (usually primary) key
if (theseKeys.Count != otherKeys.Count)
throw Error.BadArgument("S0128: Association arguments (FK and ref'd PK) don't match");
// we first create the table, with the JoinID, and we MUST complete the table later, with the Join() method
var otherTableExpression = new TableExpression(otherTableType, DataMapper.GetTableName(otherTableType, builderContext.QueryContext.DataContext), joinID);
Expression joinExpression = null;
var createdColumns = new List<ColumnExpression>();
for (int keyIndex = 0; keyIndex < theseKeys.Count; keyIndex++)
{
// joinedKey is registered, even if unused by final select (required columns will be filtered anyway)
Expression otherKey = RegisterColumn(otherTableExpression, otherKeys[keyIndex], builderContext);
// foreign is created, we will store it later if this assocation is registered too
Expression thisKey = CreateColumn(tableExpression, theseKeys[keyIndex], builderContext);
createdColumns.Add((ColumnExpression)thisKey);
// if the key is nullable, then convert it
// TODO: this will probably need to be changed
if (otherKey.Type.IsNullable())
otherKey = Expression.Convert(otherKey, otherKey.Type.GetNullableType());
if (thisKey.Type.IsNullable())
thisKey = Expression.Convert(thisKey, thisKey.Type.GetNullableType());
var referenceExpression = Expression.Equal(thisKey, otherKey);
// if we already have a join expression, then we have a double condition here, so "AND" it
if (joinExpression != null)
joinExpression = Expression.And(joinExpression, referenceExpression);
else
joinExpression = referenceExpression;
}
// we complete the table here, now that we have all join information
otherTableExpression.Join(joinType, tableExpression, joinExpression);
// our table is created, with the expressions
// now check if we didn't register exactly the same
if ((from t in builderContext.EnumerateScopeTables() where t.IsEqualTo(otherTableExpression) select t).SingleOrDefault() == null)
{
builderContext.CurrentSelect.Tables.Add(otherTableExpression);
foreach (var createdColumn in createdColumns)
builderContext.CurrentSelect.Columns.Add(createdColumn);
}
return otherTableExpression;
}
