问题描述
我想使用动态,以便能够选择要定义的列以及我想让数据库设置DEFAULT
值的列。
是否可以将dynamic
插入表并返回Id
?
我在DataConnection
和ITable<>
上都尝试了各种重载,但是我唯一能达到的结果就是获取受影响的行数。
这是我的代码:
人员表架构
CREATE TABLE [dbo].[Person] (
[Id] BIGINT IDENTITY (1,1) NOT NULL,[Name] VARCHAR (50) NOT NULL,[Surname] VARCHAR (50) NOT NULL,[BirthDate] DATE DEFAULT (getdate()) NOT NULL
);
.NET Core控制台应用程序
public class Person
{
public uint Id { get; set; }
public string Name { get; set; }
public string Surname { get; set; }
public DateTime BirthDate { get; set; }
}
public class PeopleDataConnection : DataConnection
{
public PeopleDataConnection(string connectionString)
: base(ProviderName.sqlServer,connectionString)
{ }
public ITable<Person> People => this.GetTable<Person>();
}
class Program
{
static async Task Main(string[] args)
{
await using (var db = new PeopleDataConnection("Server=DESKTOP-I41VSUN;integrated Security=sspI;Database=MotoGPRiders;"))
{
var dynamicPerson = new { Name = "Cal",Surname = "Crutchlow",BirthDate = new DateTime(1985,10,29) };
var person_without_id = new Person { Name = "Valentino",Surname = "Rossi",BirthDate = new DateTime(1979,2,16) };
var affectedRowsCount = await db.InsertAsync(dynamicPerson,nameof(Person));
affectedRowsCount = await db.People
.Value(x => x.Name,person_without_id.Name)
.Value(x => x.Surname,person_without_id.Surname)
.Value(x => x.BirthDate,person_without_id.BirthDate)
.InsertAsync();
}
Console.ReadLine();
}
}
第一个插入完成了工作,但无法返回Id
,第二个插入使我可以选择列,但不能动态选择。
有没有办法做到这一点? 预先感谢!
解决方法
您可以通过InsertWithInt64IdentityAsync
函数检索标识值。这样的插入有很多重载:
var insertedId = await db.People
.Value(x => x.Name,person_without_id.Name)
.Value(x => x.Surname,person_without_id.Surname)
.Value(x => x.BirthDate,person_without_id.BirthDate)
.InsertWithInt64IdentityAsync();
您还可以过滤掉必须通过具有columnFilter
参数的重载插入的属性:
var insertedId = await db.InsertAsync(person,e => e.MemberName.In("Name","Surname","BirthDate"));
对于具有匿名类的变体,您必须创建自己的函数,该函数使用Value.Value.Value
+ InsertWithInt64IdentityAsync
调用通过反射生成调用:
public static class DynamicExtensions
{
public static IValueInsertable<T> GenerateInsertable<T>(this ITable<T> table,object obj)
{
var dynamicAccessor = TypeAccessor.GetAccessor(obj.GetType());
var accessor = TypeAccessor.GetAccessor<T>();
var objValue = Expression.Constant(obj);
IValueInsertable<T> insertable = null;
foreach (var dynamicMember in dynamicAccessor.Members)
{
var found = accessor.Members.Find(m => m.Name == dynamicMember.Name);
if (found == null)
continue;
var sourceParam = Expression.Parameter(typeof(T),"e");
var property = Expression.Lambda(Expression.MakeMemberAccess(sourceParam,found.MemberInfo),sourceParam);
Expression value = Expression.MakeMemberAccess(objValue,dynamicMember.MemberInfo);
if (value.Type != found.Type)
value = Expression.Convert(value,found.Type);
value = Expression.Lambda(value);
if (insertable == null)
{
var method = Methods.LinqToDB.Insert.T.ValueExpression.MakeGenericMethod(typeof(T),found.Type);
insertable = (IValueInsertable<T>)method.Invoke(null,new object[] { table,property,value });
}
else
{
var method = Methods.LinqToDB.Insert.VI.ValueExpression.MakeGenericMethod(typeof(T),new object[] { insertable,value });
}
}
return insertable;
}
public static long? InsertWithIdentityDynamic<T>(this ITable<T> table,object obj)
{
var insertable = GenerateInsertable(table,obj);
if (insertable == null)
return null;
return insertable.InsertWithInt64Identity();
}
public static async Task<long?> InsertWithIdentityDynamicAsync<T>(this ITable<T> table,object obj,CancellationToken cancellationToken = default)
{
var insertable = GenerateInsertable(table,obj);
if (insertable == null)
return null;
return await insertable.InsertWithInt64IdentityAsync(cancellationToken);
}
}
和用法:
var insertedId = await db.GetTable<Person>()
.InsertWithIdentityDynamicAsync(dynamicPerson);