Flask SQLAlchemy NOT NULL constraint failed on primary key
Add explicit autoincrement=True to Trips class definition:
id = db.Column(db.Integer, primary_key=True, autoincrement=True)If table is created without explicit AUTOINCREMENT, you need to pass Trips.id=NULL in order to increment it, see https://www.sqlite.org/faq.html#q1
In the version:SQLAlchemy 1.2.7Flask-SQLAlchemy 2.3.2autoincrement=True is not a required para, but be careful with your primary key definition, since you have defined 'id' column as a primary key, you should not define another column as primary key if not necessary, otherwise, you must set the value of id column by yourself when you inserting the record.
I had this same problem in a class mapped table used as a many-many with additional attribute fields. The reason the error was popping up wasn't because autoincrement wasn't explicitly defined for the primary key, but rather because the foreign_key columns also had primary_key = True. The relationship works fine with out the additional primary_keys set in the model.