A building must have a good foundation, else it risks collapse. In software development, I liken the database component to the foundation of a building.
You must design the database correctly, else you will face many difficulties, such as this one, in subsequent development.
Firstly, to establish many-to-many relationship between 2 tables, you need a third table to broker it. For example,
table1 table3 table2
projectID(primary key)+---< projectID(primary key) bizcaseName
projectName bizcaseID(primary key) >---+bizcaseID (primary key)
otherfields otherfields
Secondly, every table must have a primary key, for table3, the 2 fields are the composite primary key.
Learn more:
1.
Introduction to database design[
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2.
1NF, 2NF, 3NF and BCNF in Database Normalization | DBMS Tutorial | Studytonight[
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Do not move forward until you fix your database design.