问题
Majority of our tables in our models has a field called "intConcurrencyID" that we intended to use for concurrency checking. I believe the only way to enable this field for concurrency checking in a Database First environment is to set the Concurrency Mode to Fixed.
However, if we have huge numbers of tables per EDMX, we will have a hard time manually configuring each type per entity not to mention the possibility of some entities to be overlooked.
Do you have any ideas on how I can automate this process? It seems that T4 Template is not the way to go since the Concurrency Mode is in the CSDL not in the Code Behind..
回答1:
I looked at the edmx file before and after changing a property's concurrency mode and came up with a solution as a console app which parses the edmx file starting with the storage model for 'timestamp' columns and modifies the conceptual model by following the mappings. This is a fairly robust solution, but it has some caveats.
I'm using MSSQL 2008, for which the timestamp/rowversion is the defacto concurrency type. In my models I only use this type as a concurrency token. If you use it in other places, but have a consistent name used for all concurrency tokens instead, I've included code for this scenario that can be uncommented. If you simply use a different concurrency type and that type is unique to concurrency columns, you can change the type from 'timestamp' in this line of code:
IEnumerable<XElement> storageEntities =
from el in ssdl.Descendants(XName.Get("EntityType",ssdlNS))
where (from prop in el.Elements(XName.Get("Property",ssdlNS)) where prop.Attribute("Type").Value == "timestamp" select prop).Count()>0
select el;
If your concurrency pattern is more complicated, this code won't suffice.
That being said, I whipped this up in about an hour and ran it and it worked great for me on a model with nearly 200 entities, saving me a lot of annoyance going through the sluggish edmx designer, so I'm sure others will benefit. This is a console application so you can put this in the prebuild step of your model project to integrate it into your build process.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Xml;
using System.Xml.Linq;
namespace ConfigureConcurrency
{
class Program
{
static void Main(string[] args)
{
string edmxPath = args[0]; //or replace with a fixed path
if (edmxPath == null || edmxPath.Length == 0)
return;
string edmxNS = @"http://schemas.microsoft.com/ado/2008/10/edmx";
string ssdlNS = @"http://schemas.microsoft.com/ado/2009/02/edm/ssdl";
string csdlNS = @"http://schemas.microsoft.com/ado/2008/09/edm";
string mapNS = @"http://schemas.microsoft.com/ado/2008/09/mapping/cs";
XElement root = XElement.Load(edmxPath);
//Storage Model
XElement ssdl = root.Descendants(XName.Get("StorageModels", edmxNS)).FirstOrDefault();
//Conceptual
XElement csdl = root.Descendants(XName.Get("ConceptualModels", edmxNS)).FirstOrDefault();
//Mapping
XElement map = root.Descendants(XName.Get("Mappings", edmxNS)).FirstOrDefault();
/*
Use this code instead of the line below it, if the type of your concurrency columns is used on other non-concurrency columns
and you use the same name for every concurrency column
string ConcurrencyColumnName = "RowVersion";
IEnumerable<XElement> storageEntities =
from el in ssdl.Descendants(XName.Get("EntityType", ssdlNS))
where (from prop in el.Elements(XName.Get("Property", ssdlNS)) where prop.Attribute("Name").Value == ConcurrencyColumnName select prop).Count() > 0
select el;
*/
IEnumerable<XElement> storageEntities =
from el in ssdl.Descendants(XName.Get("EntityType",ssdlNS))
where (from prop in el.Elements(XName.Get("Property",ssdlNS)) where prop.Attribute("Type").Value == "timestamp" select prop).Count()>0
select el;
//for each timestamp column, find the mapping then find the conceptual model property and establish the concurrency mode
foreach(XElement storageEntity in storageEntities)
{
//Get the mapping
XElement mapping = (from el in map.Descendants(XName.Get("EntityTypeMapping",mapNS)) where el.Element(XName.Get("MappingFragment",mapNS)).Attribute("StoreEntitySet").Value == storageEntity.Attribute("Name").Value select el).FirstOrDefault();
if (mapping != null)
{
//Get the column mapping
XElement column = (from el in storageEntity.Descendants(XName.Get("Property",ssdlNS)) where el.Attribute("Type").Value == "timestamp" select el).FirstOrDefault();
string columnName = column.Attribute("Name").Value;
XElement columnMapping = (from el in mapping.Descendants(XName.Get("ScalarProperty",mapNS)) where el.Attribute("ColumnName").Value == columnName select el).FirstOrDefault();
string propertyName = columnMapping.Attribute("Name").Value;
//Get the conceptual schema namespace and type name
string[] split = mapping.Attribute("TypeName").Value.Split('.');
string ns="", typeName =split[split.Length-1];
for (int i = 0; i < split.Length-1; i++)
{
if (i>0)
ns+=".";
ns += split[i];
}
//Find the entry in the conceptual model
XElement schema = (from el in csdl.Elements(XName.Get("Schema",csdlNS)) where el.Attribute("Namespace").Value == ns select el).FirstOrDefault();
if (schema != null)
{
//Find the entity type
XElement entity = (from el in schema.Descendants(XName.Get("EntityType",csdlNS)) where el.Attribute("Name").Value == typeName select el).FirstOrDefault();
//Find the property
XElement concurrencyProperty = (from el in entity.Elements(XName.Get("Property",csdlNS)) where el.Attribute("Name").Value == propertyName select el).FirstOrDefault();
//Set concurrency mode to fixed
concurrencyProperty.SetAttributeValue("ConcurrencyMode", "Fixed");
}
}
}
//Save the modifications
root.Save(edmxPath);
}
}
}
回答2:
Solved my similar problem with the above console app. But if you are running a later version of Entity Framework, be sure to update references to schemas. I am using EF 5 and for me I used the following lines:
string edmxNS = @"http://schemas.microsoft.com/ado/2009/11/edmx";
string ssdlNS = @"http://schemas.microsoft.com/ado/2009/11/edm/ssdl";
string csdlNS = @"http://schemas.microsoft.com/ado/2009/11/edm";
string mapNS = @"http://schemas.microsoft.com/ado/2009/11/mapping/cs";
来源：https://stackoverflow.com/questions/11980516/automating-concurrencymode-set-to-fix-in-edmx