Have they fixed the update situation yet? I remember that you had to select 
something before you could update it. (At least previously)

Regards,

Greg

Dr Greg Low

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From: ozdotnet-boun...@ozdotnet.com [mailto:ozdotnet-boun...@ozdotnet.com] On 
Behalf Of David Rhys Jones
Sent: Tuesday, 20 September 2016 7:20 PM
To: ozDotNet <ozdotnet@ozdotnet.com>
Subject: Re: Entity Framework - the lay of the land


I've been working with EF now for a few years,  here's a list of what went 
wrong / what went right.

Large public Website

Good:
    No complex queries in EF, anything more than a couple of tables and a 
stored procedure is called.
    All objects from EF were transformed into new objects for use in the website
Bad:
   The context was shared between processes and thusly began to grow after an 
hour or two, causing a slowdown of EF. Regular flushing solved this
  Updates into the database set the FK property but did not attach the object, 
this resulted in data being correct for a moment, but then overwritten with the 
original values when the savechanges was called.


Large Multinational Bank - Bulk Processing
   Good:
       Most processing was done without EF,
      The website used EF to query the same data.
   Bad:
       Framework implemented IEnumerable as each interface, thus       
service.GetClients().Count()  resulted in the entire table being returned. 
Changing the interface to IQueryable allowed the DB to do a count(*)

Large Multinational,  low use public website.
   Good:
      EF context is queried and disposed of as soon as possible, leaving the 
website responsive
   Bad:
     Bad design of the database has resulted in needless queries bringing back 
data that is not used. All EF generated queries are complicated.
     A mixture of stored procedures and EF context is used within a process 
resulting in incorrect values.


I quite like EF, it's efficient to write queries in if you know what is being 
generated at the database level. I always output the SQL query to the debug 
window so I know what is being passed to the DB.
But if the query is not self-contained and requires a lot of tables, then a 
specific stored procedure should be used.  However, do not update with a stored 
procedure if you are using Entity to read back the values. Do POCO updates and 
read the linked objects and attach them correctly.

Davy.



Si hoc legere scis nimium eruditionis habes.


On Tue, Sep 20, 2016 at 10:03 AM, David Connors 
<da...@connors.com<mailto:da...@connors.com>> wrote:
On Tue, 20 Sep 2016 at 13:59 Greg Low (罗格雷格博士) 
<g...@greglow.com<mailto:g...@greglow.com>> wrote:
I often get coy when I hear comparisons with Stack Overflow, Twitter, Facebook, 
Blog Engines, etc. though.
Most of those platforms are happy to just throw away transactions when the 
going gets heavy.
Also, most of their workloads are read-only and so highly cacheable at every 
layer of whatever architecture you choose.

Once you throw consistency and transaction isolation under the bus shit gets 
pretty easy pretty quick.

David.

--
David Connors
da...@connors.com<mailto:da...@connors.com> | @davidconnors | LinkedIn | +61 
417 189 363

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