/// <summary>
/// Generates a relationship query between two table
/// </summary>
/// <typeparam name="T">The type of left table</typeparam>
/// <typeparam name="TOther">The type of right table</typeparam>
/// <param name="leftTableColumn">The column of left table</param>
/// <param name="rightOtherTableColumn">The column of right table</param>
/// <returns></returns>
public static IQuery <TOther> JoinWith <T, TOther>(this IQuery <T> query, Expression <Func <T, object> > leftTableColumn, Expression <Func <TOther, object> > rightOtherTableColumn)
{
IQuery <TOther> result = Activator.CreateInstance(typeof(Entity <TOther>), args: query.ConnectionString) as Entity <TOther>;
result.FromStatement += query.FromStatement;
result.WhereStatement.Append(query.WhereStatement);
result.JoinStatement.Append(query.JoinStatement);
result.OrderByAscendingStatement.Append(query.OrderByAscendingStatement);
result.OrderByDescendingStatement.Append(query.OrderByDescendingStatement);
result.SkipCount = query.SkipCount;
result.TakeCount = query.TakeCount;
JoinExpressionResult joinExpression = ExpressionUtil.GetJoinExpression <TOther>(rightOtherTableColumn.Body);
joinExpression.FromColumnName = ExpressionUtil.GetJoinExpression <T>(leftTableColumn).ColumnName;
query.JoinStatement.Append(" JOIN ");
query.JoinStatement.Append(joinExpression.TableName);
query.JoinStatement.Append(" ");
query.JoinStatement.Append(joinExpression.TableName.ToLower());
query.JoinStatement.Append(" ON ");
query.JoinStatement.Append(typeof(T).Name.ToLower());
query.JoinStatement.Append(".");
query.JoinStatement.Append(joinExpression.FromColumnName);
query.JoinStatement.Append(" = ");
query.JoinStatement.Append(joinExpression.TableName.ToLower());
query.JoinStatement.Append(".");
query.JoinStatement.Append(joinExpression.ColumnName);
result.JoinStatement.Append(query.JoinStatement);
return(result);
}
/// <summary>
/// Generates a relationship query between two table
/// </summary>
/// <typeparam name="TRight">The type of right table</typeparam>
/// <param name="rightExpression">The expression of right table</param>
/// <returns></returns>
public static JoinExpressionResult GetJoinExpression <TRight>(object rightExpression)
{
JoinExpressionResult joinExpressionResult = new JoinExpressionResult();
if (rightExpression is LambdaExpression)
{
LambdaExpression lambdaExpression = rightExpression as LambdaExpression;
if (lambdaExpression.Body is MemberExpression)
{
MemberExpression memberExpression = lambdaExpression.Body as MemberExpression;
joinExpressionResult.TableName = typeof(TRight).Name;
joinExpressionResult.ColumnName = memberExpression.Member.Name;
}
else if (lambdaExpression.Body is UnaryExpression)
{
UnaryExpression unaryExpression = lambdaExpression.Body as UnaryExpression;
if (unaryExpression.Operand is MemberExpression)
{
MemberExpression memberExpression = unaryExpression.Operand as MemberExpression;
joinExpressionResult.TableName = typeof(TRight).Name;
joinExpressionResult.ColumnName = memberExpression.Member.Name;
}
}
}
else if (rightExpression is MemberExpression)
{
MemberExpression memberExpression = rightExpression as MemberExpression;
if (memberExpression.NodeType == ExpressionType.MemberAccess)
{
joinExpressionResult.TableName = typeof(TRight).Name;
joinExpressionResult.ColumnName = memberExpression.Member.Name;
}
else if (memberExpression.NodeType == ExpressionType.Convert)
{
joinExpressionResult.TableName = typeof(TRight).Name;
joinExpressionResult.ColumnName = "";
}
}
else if (rightExpression is UnaryExpression)
{
UnaryExpression unaryExpression = rightExpression as UnaryExpression;
if (unaryExpression.Operand is MemberExpression)
{
MemberExpression memberExpression = unaryExpression.Operand as MemberExpression;
joinExpressionResult.TableName = typeof(TRight).Name;
joinExpressionResult.ColumnName = memberExpression.Member.Name;
}
}
return(joinExpressionResult);
}
