private string ProcessRelation(Expression fullExpression, Expression leftExpression, string memberName)
{
if (leftExpression.NodeType == ExpressionType.Convert)
{
leftExpression = ((UnaryExpression)leftExpression).Operand;
}
var parentMetaData = _metaData[leftExpression];
if (parentMetaData != null)
{
if (_metaData.ContainsKey(fullExpression))
{
return(null); // relation already visited
}
var iterator = GetRootIterator(parentMetaData.Iterator);
var relation = parentMetaData.Schema.Relations[memberName];
var leftAlias = _relationAliases[iterator][parentMetaData.Key];
if (relation != null && relation.IsToOne)
{
if (!_relationAliases[iterator].ContainsKey(relation))
{
var sqlJoin = new SqlJoinDefinition(
new SqlJoinPart(parentMetaData.Schema, relation.LocalField, leftAlias),
new SqlJoinPart(relation.ForeignSchema, relation.ForeignField, SqlNameGenerator.NextTableAlias())
);
CurrentQuery.Joins.Add(sqlJoin);
_relationAliases[iterator][relation] = sqlJoin.Right.Alias;
}
_metaData[fullExpression] = new ExpressionMetaData {
Iterator = iterator, Relation = relation, Schema = relation.ForeignSchema
};
}
else if (relation == null)
{
return(leftAlias + "." + (_schema.FieldsByFieldName[memberName]?.MappedName ?? memberName));
}
}
return(null);
}
public virtual string JoinSql(SqlJoinDefinition j)
{
return($"{(j.Type == SqlJoinType.Inner ? "inner" : "left outer")} join {QuoteTable(j.Right.Schema.MappedName)} {j.Right.Alias} on {QuoteField(j.Left.Alias + "." + j.Left.Field.MappedName)}={QuoteField(j.Right.Alias + "." + j.Right.Field.MappedName)}");
}