Different types of fields have different lengths, some are large and some are small, and cannot exceed the specified length;
Attachments may contain many file types, not just pictures, so it is recommended to upload them to a certain location on the server or cloud storage (such as Qiniu), and then the database uses a field to save the server file path or cloud storage URL;
When saving emails to SQLite, give a receiving time, and all emails will be sorted in descending order by receiving time;
You can specify an auto-increment ID when designing the database, and a unique ID will be automatically generated every time you create an email;
If the interface for getting emails has a unique identifier, you can save the unique identifier and set it as a unique key or primary key, and then compare it in the database every time you get the email. If there is one, it will not be saved.
I suggest you learn the basic knowledge of databases. Judging from your question, it seems that you have little understanding of databases. Come on. . .
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Different types of fields have different lengths, some are large and some are small, and cannot exceed the specified length;
Attachments may contain many file types, not just pictures, so it is recommended to upload them to a certain location on the server or cloud storage (such as Qiniu), and then the database uses a field to save the server file path or cloud storage URL;
When saving emails to SQLite, give a receiving time, and all emails will be sorted in descending order by receiving time;
You can specify an auto-increment ID when designing the database, and a unique ID will be automatically generated every time you create an email;
If the interface for getting emails has a unique identifier, you can save the unique identifier and set it as a unique key or primary key, and then compare it in the database every time you get the email. If there is one, it will not be saved.
I suggest you learn the basic knowledge of databases. Judging from your question, it seems that you have little understanding of databases. Come on. . .