linq to sql 乐观锁

女爷i 2022-06-12 05:14 155阅读 0赞

class Program  
    \{   
        static void Main(string\[\] args)  
        \{   
            string sql = "data source=localhost;initial catalog=test;integrated security=true";  
            DataContext dc = new DataContext(sql);

Table<AuthorEntity> authors = dc.GetTable<AuthorEntity>();  
            AuthorEntity aAuthor = (from author in authors  
                                    where author.Name == "tony"  
                                    select author).Single();  
             
            aAuthor.Age = 65;

SqlConnection conn = new SqlConnection(sql);  
            SqlCommand cmd = conn.CreateCommand();  
            cmd.CommandText = "update author set name='tonytonlx' where id = 2;";  
            cmd.CommandType = System.Data.CommandType.Text;

conn.Open();  
            cmd.ExecuteNonQuery();  
            conn.Close();

try  
            \{   
                dc.SubmitChanges(ConflictMode.ContinueOnConflict);  
            \}  
            catch (ChangeConflictException ex)  
            \{

foreach (System.Data .Linq .ObjectChangeConflict occ in dc.ChangeConflicts )  
                \{

AuthorEntity authorEntity = occ.Object as AuthorEntity;  
                    Console.WriteLine(authorEntity.ToString());

//以当前客户端中的值为准  
                    //occ.Resolve(System.Data.Linq.RefreshMode.OverwriteCurrentValues);//tonytonglx,99 保留数据库值  
                    //occ.Resolve(System.Data.Linq.RefreshMode.KeepCurrentValues);//tony 65   覆盖数据库  
                    occ.Resolve(System.Data.Linq.RefreshMode.KeepChanges);//tonytonglx,65 合并数据库值  
                    foreach (System.Data.Linq.MemberChangeConflict mcc in occ.MemberConflicts )  
                    \{   
                        Console.WriteLine("CurrentValue = " + mcc.CurrentValue);  
                        Console.WriteLine("OriginalValue = " + mcc.OriginalValue);  
                        Console.WriteLine("DatabaseValue = " + mcc.DatabaseValue);  
                    \}

Console.WriteLine(authorEntity.ToString());

\}                 
            \}  
            finally  
            \{   
                try  
                \{   
                    dc.SubmitChanges(ConflictMode.ContinueOnConflict);  
                \}  
                catch (ChangeConflictException conflict)  
                \{   
                    Console.WriteLine(conflict);  
                \}  
            \}

\-----------------------------------

namespace LinqToSQLTest  
\{  
    \[Table(Name="dbo.Author")\]  
    class AuthorEntity  
    \{  
  
        \[Column(Name="Id", IsPrimaryKey= true,DbType="int not null")\]  
        public int Id \{ get; set; \}

\[Column(Name = "name", DbType = "nvarchar(50) not null",UpdateCheck=UpdateCheck .Always) \]  
        public string Name \{ get; set; \}

\[Column(Name="age", DbType="int not null",UpdateCheck=UpdateCheck.WhenChanged)\]  
        public int Age \{ get; set; \}

\[Column(Name="Address",DbType="nvarchar(50) not null",UpdateCheck=UpdateCheck.Never)\]  
        public string Address \{ get; set; \}

private EntitySet<BookEntity> \_Books = new EntitySet<BookEntity>();

\[Association(Name = "FK\_Book\_Author",  OtherKey = "AuthorId", ThisKey = "Id")\]

public EntitySet<BookEntity> Books \{ get; set; \}  
        //public EntitySet<BookEntity> Books  
        //\{  
        //    get \{ \};  
        //    set\_  
        //    //get \{  
                 
        //    //    return this.\_Books; \}  
        //    //set \{  
        //    //    Console.Write (\_Books.Count());  
        //    //    this.\_Books.Assign(value); \}  
        //\}

public override string ToString()  
        \{  
            return "Id:" + this.Id + ",Name=" + this.Name + ",Age=" + this.Age + ",Address=" + this.Address;  
        \}  
    \}  
\}

\----------------------------------------------

namespace LinqToSQLTest  
\{  
    \[Table(Name="dbo.Book")\]  
    class BookEntity  
    \{  
        \[Column(Name="Id",IsPrimaryKey=true,DbType="int not null")\]  
        public int Id \{ get; set; \}  
         
        \[Column(Name="title",DbType="nvarchar(50) not null")\]  
        public string Title \{ get; set; \}  
         
        \[Column(Name="authorId",DbType="int not null")\]  
        public int AuthorId \{ get; set; \}  
        
        \[Column(Name="press",DbType = "nvarchar(50) not null")\]  
        public string Press \{ get; set; \}  
         
        \[Column(Name="Price",DbType = "float not null")\]  
        public double Price \{ get; set; \}

\[Column(Name="date",DbType = "datetime not null")\]  
        public DateTime Date\{get;set;\}

private EntityRef<AuthorEntity> \_Author;

\[Association(Name="FK\_Book\_Author",Storage="\_Author",IsForeignKey=true,OtherKey="Id",ThisKey="AuthorId")\]  
        public AuthorEntity Author  
        \{  
            get \{ return this.\_Author.Entity; \}  
            set \{ this.\_Author.Entity = value; \}  
        \}

\}  
\}