当你在处理数据库或类似的数据存储系统时,遇到“cannot update entity without key”的错误通常意味着你尝试更新一个实体,但是这个实体在数据库中并没有一个有效的键(key)来标识它。为了解决这个问题,你可以按照以下步骤操作: 确认实体是否已存在且拥有键(key): 在进行更新操作之前,确保你尝试更新的实体已经在数据...
The property '{property}' of the argument '{argument}' cannot be null. AttributeNotOnEntityTypeProperty(Object, Object, Object) The [{attribute}] attribute may only be specified on entity type properties. Remove the attribute from '{type}.{propertyName}'. AutoIncludeNavigationCycle(Object) ...
Gets the type for the context, if no type is defined, then DBContext will be returned Extensions Gets a list of Extensions as configured, such as the type of database being leveraged IsFrozen Used to determine if the Context is open for further configuration. If true, the system cannot fur...
CREATE PROCEDURE [dbo].[People_Insert] @Name [nvarchar](max) AS BEGIN INSERT INTO [People] ([Name]) OUTPUT INSERTED.[Id] VALUES (@Name); END For updates Copy CREATE PROCEDURE [dbo].[People_Update] @Id [int], @Name_Original [nvarchar](max), @Name [nvarchar](max) AS BEGIN UPDATE ...
The entity or complex type cannot be constructed in a LINQ to Entities query. The entity type 'UserRole' was not found. Ensure that the entity type has been added to the model. The entity type does not declare a navigation property with the name The entity type is not part of the mode...
Unlike entity types, query types do not have keys defined on them and cannot be inserted, deleted or updated (i.e. they are read-only), but they can be returned directly by queries. Some of the usage scenarios for query types are: Mapping to views without primary keys Mapping to tables...
This method should not be overridden. Instead, override getAttribute(int index). Specified by: getAttribute in interface AttributeList Parameters: name - the name of the attribute. Returns: the value of the attribute. The class of the returned value a Java type determined by this Entity Object'...
This table cannot be deleted. Access Restriction None. Description of Alarm Objects entConfigChange OID Object Syntax Description Implemented Specifications 1.3.6.1.2.1.47.2.0.1 entConfigChange NA This object indicates that an entity (either a board or a subcard) was inserted, pulled out, reset, ...
This table cannot be deleted. Access Restriction None. Description of Alarm Objects entConfigChange OID Object Syntax Description Implemented Specifications 1.3.6.1.2.1.47.2.0.1 entConfigChange NA This object indicates that an entity (either a board or a subcard) was inserted, pulled out, reset, ...
Primary key properties can only be of one of the basic types (any type in Table 1, except arrays and enumerations), but cannot be complex types or other entity’s types.FieldsNew since Entity Framework Core 1.1 is the possibility of mapping fields, of any visibility. This comes in handy...