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[Source] EF Entities of append type "XXXX" fail because other...

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Posted on 5/12/2021 9:43:53 AM | | |
EF appends an entity of type "XXXX" that fails because another entity of the same type already has the same primary key value. When using the "Attach" method or setting the entity's state to "Unchanged" or "Modified"

Because other entities of the same type already have the same primary key value. This behavior can occur when using the "Attach" method or when setting the status of an entity to "Unchanged" or "Modified" if any entity in the drawing has a conflicting key value
This may be because some entities are new and have not yet received a database-generated key-value (new entity), in which case the graph is tracked using the "Add" method or the "Added" entity state, and then the state of the non-new entity is set to "Unchanged" or "Modified" accordingly.
In fact, this error is that when EF opens a transaction, there is already a data with the same primary key in the context of EF, and I personally encounter this problem in various situations:

Situation 1:

Modifying, iterating through the same data in a table (e.g., iterating the inventory quantity of the same item), this case should be the first time the context cache is not cleared

The code is as follows:


The loop here does not report an error the first time, and the second time it will be errored

Solution:


Situation 2:

The loop operation first adds a piece of data, and then modifies the data

The code is as follows:


Errors are also reported here, especially for new EFs or new entities

Solution:








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Posted on 9/22/2021 8:55:57 PM |
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