DbContext不支持打开一个显式事务来执行读取操作。它依赖于SQL Server的自动提交事务(Autocommit Transaction) (或者隐式事务(Implicit Transaction)——如果你启用了它们的话,但那相对来说不是常见的操作)。自动提交事务(或者隐式事务)将会使用数据库引擎被配置的默认事务隔离级别(对SQL Server来说就是READ COMMITTED)。
SETIMPLICIT_TRANSACTIONSON DECLARE@iINT SET@i=0 WHILE@i<100000 BEGIN SELECTId FROMdbo.Users WHEREId=@i SET@i=@i+1 END COMMIT; SETIMPLICIT_TRANSACTIONSOFF --- -- 显示事务 -- 6 秒 DECLARE@iINT SET@i=0 BEGINTRAN WHILE@i<100000 BEGIN SELECTId FROMdbo.Users WHEREId=@i SET@i=@i+...
info: 9/29/2022 11:42:34.776 RelationalEventId.CommandExecuted[20101] (Microsoft.EntityFrameworkCore.Database.Command) Executed DbCommand (25ms) [Parameters=[@p0='MyBlog' (Nullable = false) (Size = 4000)], CommandType='Text', CommandTimeout='30'] SET IMPLICIT_TRANSACTIONS OFF; SET NOCOUNT...
this error is due to entity framework creating an implicit transaction during the savechanges() call. the best way to work around the error is to use a different pattern (i.e., not saving while in the midst of reading) or by explicitly declaring a transaction. here ar...
info: 2022-07-10 17:24:28.740 RelationalEventId.CommandExecuted[20101] (Microsoft.EntityFrameworkCore.Database.Command) Executed DbCommand (52ms) [Parameters=[@p0='Foo' (Size = 4000)], CommandType='Text', CommandTimeout='30'] SET IMPLICIT_TRANSACTIONS OFF; ...
As we'll see later, Entity Framework wraps all write operations within an explicit database transaction by default. Coupled with aREAD COMMITTEDisolation level - the default on SQL Server - this suits the needs of most business transactions. This is especially the case if you rely onoptimistic...
When AutoTransactionBehaviour is the default (AutoTransactionBehaviour.WhenNeeded), autocommit (MySql "SET autocommit=0") is set to 0 somewhere, which is wrong (it doesn't turn off implicit transactions, it just turns off committing them automatically). InnoDB starts implicit transactions ALWAYS, ...
SELECT a FROM T (Transact-SQL)SELECT n.a FROM T AS a (Entity SQL)SELECT T.a FROM T (Entity SQL with implicit alias) 1. 2. 3. 若不想指定別名時,就要指定表格的名稱ADO.NET Entity Framework會做內隱式的別名轉換。Transact-SQL 中若要提取所有欄位,我們會用 * 來指示,但是這在 Entity SQL...
Entity Framework Core does not support implicit mapping to computed columns, which are columns whose values are not physically stored in a table but instead come from SQL formulas. An example of a computed column is combining first and last name into a full name column, which can be achieved...
SELECTaFROMT (Transact-SQL)SELECTn.aFROMTASa (EntitySQL)SELECTT.aFROMT (EntitySQLwithimplicit alias) AI代码助手复制代码 若不想指定別名時,就要指定表格的名稱ADO.NET Entity Framework會做內隱式的別名轉換。Transact-SQL 中若要提取所有欄位,我們會用 * 來指示,但是這在 Entity SQL 中是不支援的,必須要...