transactions

问题 I am developing application in N-Tier Architecture. as we all know that we need to implement transactions while insert/update/delete operation. please tell me how to use transaction in c#.net in N-Tier architecture. my architecture is like this Applicationform->middle_Layre->Factory->DataAccessLayre->StoredProcedure->Table in application form i create object of middleLayer and pass data in Insert/update/delete function of middle layer. i am creating object of sqlcommand in factoryclass and

问题 I am developing application in N-Tier Architecture. as we all know that we need to implement transactions while insert/update/delete operation. please tell me how to use transaction in c#.net in N-Tier architecture. my architecture is like this Applicationform->middle_Layre->Factory->DataAccessLayre->StoredProcedure->Table in application form i create object of middleLayer and pass data in Insert/update/delete function of middle layer. i am creating object of sqlcommand in factoryclass and

问题 I am developing application in N-Tier Architecture. as we all know that we need to implement transactions while insert/update/delete operation. please tell me how to use transaction in c#.net in N-Tier architecture. my architecture is like this Applicationform->middle_Layre->Factory->DataAccessLayre->StoredProcedure->Table in application form i create object of middleLayer and pass data in Insert/update/delete function of middle layer. i am creating object of sqlcommand in factoryclass and

问题 I am developing an application which communicates with an SQL Server 2005 database to execute some stored procedures. My client demands that all transactions be managed on the C# side and not by SQL Server, and so I am using System.Transactions.TransactionScope when accessing the database. However, I have just seen the System.Transactions.Transaction datatype, and I am confused... What are the main pros/cons of each type? Which one should I use? Please note that I must also use Enterprise

问题 I am developing an application which communicates with an SQL Server 2005 database to execute some stored procedures. My client demands that all transactions be managed on the C# side and not by SQL Server, and so I am using System.Transactions.TransactionScope when accessing the database. However, I have just seen the System.Transactions.Transaction datatype, and I am confused... What are the main pros/cons of each type? Which one should I use? Please note that I must also use Enterprise

问题 What's the point to enclose select statements in a transaction? I think select statements are just "GET" data from the database, they don't have chance to rollback something, because you just can't change the data. So, does that to say we never need put select statements in a transaction? Am I right? Thanks. 回答1: You're right: at the standard isolation level, read committed , you do not need to wrap select statements in transactions. Select statements will be protected from dirty reads

问题 Why doesn't ActiveRecord rollback changes in nested transactions after exception was risen in a child block? Here are examples: 1. >> Client.transaction do ?> Client.create(:name => 'Pavel') >> Client.transaction do ?> Client.create(:name => 'Elena') >> raise ActiveRecord::Rollback >> end >> end => nil >> Client.all.map(&:name) => ["Pavel", "Elena"] # instead of [] 2. >> Client.transaction do ?> Client.create(:name => 'Pavel') >> Client.transaction(:requires_new => true) do ?> Client.create(

问题 Why doesn't ActiveRecord rollback changes in nested transactions after exception was risen in a child block? Here are examples: 1. >> Client.transaction do ?> Client.create(:name => 'Pavel') >> Client.transaction do ?> Client.create(:name => 'Elena') >> raise ActiveRecord::Rollback >> end >> end => nil >> Client.all.map(&:name) => ["Pavel", "Elena"] # instead of [] 2. >> Client.transaction do ?> Client.create(:name => 'Pavel') >> Client.transaction(:requires_new => true) do ?> Client.create(

问题 I am reading a manual about innodb transactions but still, there is lots of unclear stuff to me. For instance, I don't quite understand to the following behaviour: -- client 1 -- client 2 mysql> create table simple (col int) engine=innodb; mysql> insert into simple values(1); Query OK, 1 row affected (0.00 sec) mysql> insert into simple values(2); Query OK, 1 row affected (0.00 sec) mysql> select @@tx_isolation; +-----------------+ | @@tx_isolation | +-----------------+ | REPEATABLE-READ | +-

问题 I am reading a manual about innodb transactions but still, there is lots of unclear stuff to me. For instance, I don't quite understand to the following behaviour: -- client 1 -- client 2 mysql> create table simple (col int) engine=innodb; mysql> insert into simple values(1); Query OK, 1 row affected (0.00 sec) mysql> insert into simple values(2); Query OK, 1 row affected (0.00 sec) mysql> select @@tx_isolation; +-----------------+ | @@tx_isolation | +-----------------+ | REPEATABLE-READ | +-