問(wèn)題描述

當(dāng)我發(fā)出SaveChanges()"時(shí)，Entity Framework 中的默認(rèn)事務(wù)隔離級(jí)別是什么?我在任何地方都找不到它.應(yīng)該是可序列化"嗎?

What is the default transaction isolation level in Entity Framework when I issue "SaveChanges()"? I can not find it anywhere. Shall it be "Serializable"?

推薦答案

SaveChanges 使用當(dāng)前存儲(chǔ)提供程序的 DbTransaction 實(shí)現(xiàn).這意味著默認(rèn)事務(wù)隔離級(jí)別設(shè)置為數(shù)據(jù)庫(kù)服務(wù)器的默認(rèn)值.在 SQL Server 中，它是 READ COMMITTED.如果要更改隔離級(jí)別，可以使用 TransactionScope.您還可以在派生上下文中覆蓋 SaveChanges 并在覆蓋方法中直接將 base.SaveChanges() 包裝到范圍.

SaveChanges uses implementation of DbTransaction for current store provider. It means that default transaction isolation level is set to default value for the database server. In SQL Server it is READ COMMITTED. If you want to change isolation level you can use TransactionScope. You can also override SaveChanges in your derived context and wrap base.SaveChanges() to the scope directly in overriden method.

public override void SaveChanges()
{
    // Default isolation level for TransactionScope is Serializable
    using (var scope = new TransactionScope())
    {
        base.SaveChanges();
        scope.Complete();
    }
}

您可以進(jìn)一步改進(jìn)此代碼以允許您將隔離級(jí)別傳遞給 SaveChanges 等.一旦您開(kāi)始更改隔離級(jí)別，您應(yīng)該始終如一地執(zhí)行此操作.這意味著每次要運(yùn)行事務(wù)時(shí)都應(yīng)該定義隔離級(jí)別，因?yàn)?隔離級(jí)別是按連接配置的 和連接在使用連接池時(shí)被重用.

You can further improve this code to allow you passing isolation level to SaveChanges etc. Once you start changing isolation levels you should do it consistently. It means you should define isolation level each time you want to run a transaction because isolation level is configured per connection and connections are reused when using connection pooling.

EF6 中的默認(rèn)事務(wù)級(jí)別已更改為 READ COMMITTED SNAPSHOT

Default transaction level in EF6 has changed to READ COMMITTED SNAPSHOT

這篇關(guān)于當(dāng)我發(fā)出“SaveChanges()"時(shí)，Entity Framework 中的默認(rèn)事務(wù)隔離級(jí)別是什么?的文章就介紹到這了，希望我們推薦的答案對(duì)大家有所幫助，也希望大家多多支持html5模板網(wǎng)！