在对实体框架进行一些研究时,我发现了以下帖子:
http://romiller.com/2011/05/23/ef-4-1-multi-tenant-with-code-first/ http://romiller.com/2011/05/23/ef-4-1-multi-tenant-with-code-first/
它并没有给我一个单独的 dbContext 来使用,但它只使用一个连接(这是我不想使用多个 dbContext 的原因)。设置后如下代码:
public class oraDbContext : DbContext
{
static oraDbContext() {
Database.SetInitializer<oraDbContext>(null);
}
private oraDbContext(DbConnection connection, DbCompiledModel model)
: base(connection, model, contextOwnsConnection: false) { }
public DbSet<SomeTable1> SomeTable1 { get; set; }
public DbSet<SomeTable2> SomeTable2 { get; set; }
private static ConcurrentDictionary<Tuple<string, string>, DbCompiledModel> modelCache = new ConcurrentDictionary<Tuple<string, string>, DbCompiledModel>();
public static oraDbContext Create(string schemaName, DbConnection connection) {
var compiledModel = modelCache.GetOrAdd(
Tuple.Create(connection.ConnectionString, schemaName),
t =>
{
var builder = new DbModelBuilder();
builder.Configurations.Add<SomeTable1>(new SomeTable1Map(schemaName));
builder.Configurations.Add<SomeTable2>(new SomeTable2Map(schemaName));
var model = builder.Build(connection);
return model.Compile();
});
return new oraDbContext(connection, compiledModel);
}
}
这当然要求我的映射文件设置如下:
public class DailyDependencyTableMap : EntityTypeConfiguration<DailyDependencyTable>
{
public SomeTableMap(string schemaName) {
this.ToTable("SOME_TABLE_1", schemaName.ToUpper());
//Map other properties and stuff
}
}
编写使用多个模式的查询有点烦人,但目前它可以满足我的需要:
using (var connection = new OracleConnection("a connection string")) {
using (var schema1 = oraDbContext.Create("SCHEMA1", connection))
using (var schema2 = oraDbContext.Create("SCHEMA2", connection)) {
var query = ((from a in schema1.SomeTable1 select new { a.Field1 }).ToList())
.Concat((from b in schema2.SomeTable1 select new { b.Field1 }).ToList())
}
}