Missing constraint index

I'm sorry, could you please provide more context or information about the issue you are facing? It would help me to better understand the problem and provide a more accurate solution.

相关问题

gurobi 'Missing constraint index'

"Missing constraint index" error in Gurobi usually occurs when you are trying to modify or delete a constraint that does not exist in the model. This error can also occur if you are trying to add a new constraint with an index that already exists.

To resolve this error, you can try the following steps:

1. Check if the constraint index you are trying to modify or delete actually exists in the model. You can use the getConstrs() method to get a list of all the constraints in the model and their indices.

2. If you are trying to add a new constraint, make sure that the constraint index you are using does not already exist in the model. You can use the same getConstrs() method to check for existing constraint indices.

3. Check if you have any typos or errors in the constraint index you are using. Make sure that the index is a valid integer and that it matches the format of the other constraint indices in the model.

4. If none of the above steps work, try resetting the model and adding all the constraints again from scratch.

I hope this helps you resolve the "Missing constraint index" error in Gurobi.

mysql外键设置错误代码： 1822 Failed to add the foreign key constraint. Missing index for constraint...

这个错误代码说明您在设置外键约束时遇到了问题。具体地说，错误代码1822表示添加外键约束失败，因为缺少用于约束的索引。

在MySQL中，为了创建一个外键约束，您需要确保被引用的列（即外键列）上存在一个索引。如果没有为外键列创建索引，MySQL将无法创建该约束，并且会抛出1822错误。

要解决这个问题，您可以按照以下步骤进行操作：

1. 确保被引用的列上存在索引。如果没有，请先为该列创建索引。
2. 确保外键列和被引用列的数据类型、长度等属性匹配。外键列必须与被引用列具有相同的数据类型和长度。
3. 如果您已经创建了索引但仍然遇到问题，请确保索引名称唯一。如果存在重复的索引名称，尝试使用不同的名称再次创建外键约束。

请注意，创建外键约束还可能受到其他因素的限制，如表引擎类型、字符集等。如果问题仍然存在，请提供更多的细节和表结构信息，以便更好地帮助您解决问题。