search

brucezhang80 / dapper-dot-net

Automatically exported from code.google.com/p/dapper-dot-net
Other
0 stars 0 forks source link

When column name in database doesn't match with property name... #108

Open GoogleCodeExporter opened 9 years ago

GoogleCodeExporter commented 9 years ago 
What steps will reproduce the problem?
1.Column name in database doesn't match with property name

Dapper.net works just perfect when my column name matches entity name. 
Otherwise we have either two options 
1. Return columns with alias "customer_alias as ID "
2. Proposed customized code below in dapper.net

We do not have control over database queries so we had to come up with some 
kind of work around. My question is, do we have a better approach or below is 
acceptable.

If acceptable, can this be incorporated in solution due for forthcomming 
releases?

Additional information below.
GetSettableProps routine:
//Original Code
//Name = p.Name,

//Modified Code
Name = p.GetCustomAttributes(typeof(DisplayNameAttribute), true).Length > 0 ? 
p.GetCustomAttributes(typeof(DisplayNameAttribute), 
true).Cast<DisplayNameAttribute>().Single().DisplayName
                                :p.Name,

Usage in Business Entities: 
    public class Customer : EntityBase
    {
        [DisplayName("CUSTOMER_ALIAS")]//this is column name
        public int ID { get; set; }//this is entity property name

public string Customer_Name{ get; set;}//column name matches entity name

Thanks,
Mani

Original issue reported on code.google.com by chintama...@gmail.com on 26 Jul 2012 at 11:04

GoogleCodeExporter commented 9 years ago 
Using `[DisplayName]` would be a mistake; that attribute is used, for example, 
to define text on UI controls - so you'd have (in `DataGridView` etc) 
`CUSTOMER_ALIAS` instead of `ID`. 

Previously, we've always taken quite a strong position of "make the entity fit 
the data". I don't have any *technical* issues with us adding our own attribute 
to process this, other than it feels a bit "icky" (and that is coming from 
someone who uses attributes wildly). I don't have a massive opinion / stake on 
the matter, though. In some ways, maybe adding a custom dapper attribute would 
make things easier for a lot of people. Not my *preferred* option, but 
certainly a better option than looking at `DisplayNameAttribute`

Original comment by marc.gravell on 26 Jul 2012 at 11:19

GoogleCodeExporter commented 9 years ago 
We already thought about creating custom attribute but that would create 
dependency of Dapper in my multilayered architecture where entities have been 
used. So we opted for .net runtime provided attribute "DisplayName".
If Dapper use a custom attribute (in a seperate stand alone assembly) it can 
then be referenced across the ntier layer without having a dependency on dapper.
Can we expect this or *better* solution in future dapper.net release?

Original comment by chintama...@gmail.com on 26 Jul 2012 at 12:21

GoogleCodeExporter commented 9 years ago 
The best I can offer is a static event: it gives you the MemberInfo, you return 
the SQL column name. Then you can write your own implementation. I'm not going 
to make dapper look at DisplayName, but you *could* via the event

Original comment by marc.gravell on 26 Jul 2012 at 1:51

GoogleCodeExporter commented 9 years ago 
Can you provide a sample as how this event will be raised and how to provide 
the matching dbColumn name as input?

Alternative solution can be, Dapper can provide a way to pass a map 
(DBColumn-EntityName) as input (optional) to the Read method which can be use 
for mapping.

Original comment by SumitSa...@gmail.com on 30 Jul 2012 at 7:19

GoogleCodeExporter commented 9 years ago 
Here is my suggestion so far: http://stackoverflow.com/a/11704151/23354

Passing the map to Read is problematic, as that then raises the possibility of 
different Read having different Map, meaning I'd need to cache against your 
Map. Don't really fancy that...

Original comment by marc.gravell on 30 Jul 2012 at 10:44

GoogleCodeExporter commented 9 years ago 
When to expect this solution be part of release?

Original comment by SumitSa...@gmail.com on 17 Aug 2012 at 1:41

GoogleCodeExporter commented 9 years ago 
when it gets written, tested and deployed; I'll see if I can get it done this 
week

Original comment by marc.gravell on 17 Aug 2012 at 8:51

GoogleCodeExporter commented 9 years ago 
The way I achieved this is by making my private variables the same name as the 
returned column, then making the Properties English. Not exactly the bases 
solution but definitely works and takes advantage of Dapper :)

e.g.

private string customer_alias = null;

public string ID
{
get
 {
   return this.customer_alias;
 }
set
 {
   this.customer_alias = value;
 }
}

Hope this makes sense?

Original comment by Mof...@gmail.com on 7 Feb 2013 at 9:03