private string CreateParameter(object value, Type type = null)
{
var parameterName = SqlNameGenerator.NextParameterName();
SqlParameters[parameterName] = new QueryParameter(parameterName, value, type);
return(_sqlDialect.CreateParameterExpression(parameterName));
}
private string TranslateOneToMany(string functionName, MemberExpression memberExpression, LambdaExpression fieldExpression, LambdaExpression filterExpression)
{
if (!string.IsNullOrEmpty(TranslateMember(memberExpression))) // this shouldn't return any SQL
{
throw new SqlExpressionTranslatorException(memberExpression.ToString());
}
var relation = GetRelation(memberExpression.Expression, memberExpression.Member.Name);
if (relation == null)
{
throw new SqlExpressionTranslatorException(memberExpression.ToString());
}
if (fieldExpression != null && filterExpression != null && fieldExpression.Parameters[0] != filterExpression.Parameters[0])
{
throw new SqlExpressionTranslatorException(null);
}
var iterator = fieldExpression != null ? fieldExpression.Parameters[0] : filterExpression != null ? filterExpression.Parameters[0] : Expression.Parameter(relation.ElementType);
LambdaExpression relationExpression = CreateToManyFilterExpression(relation, memberExpression.Expression, filterExpression, iterator);
var template = _toManyTemplates[functionName];
if (template == null)
{
throw new NotSupportedException(functionName);
}
var alias = SqlNameGenerator.NextTableAlias();
_metaData[iterator] = new ExpressionMetaData {
Iterator = iterator, Relation = relation, Schema = relation.ForeignSchema
};
_relationAliases[iterator] = new Dictionary <object, string> {
{ relation, alias }
};
_subQueries.Push(new SubQuery());
string sqlFields = Translate(fieldExpression);
string sqlWhere = Translate(relationExpression);
string sqlJoins = (Joins.Count > 0) ? string.Join(" ", Joins.Select(join => join.ToSql(_sqlDialect))) : null;
_subQueries.Pop();
return(string.Format(template,
sqlFields,
_sqlDialect.QuoteTable(relation.ForeignSchema.MappedName) + " " + alias, sqlJoins ?? "",
sqlWhere
));
}
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);
}
