11 votes 11 votes The minimum number of tables to represent ER-Diagram such that the relational database satisfies 1NF. Databases er-diagram databases er-to-relational relational + – targate2018 asked Aug 11, 2017 targate2018 11.7k views answer comment Share Follow See all 23 Comments See all 23 23 Comments reply Show 20 previous comments Maguluri Bhaskar commented Aug 26, 2019 reply Follow Share The minimum number of tables are 4. Explanation:- Straightly we can create tables for bank,bankbranch,loan. Total tables are 3. But in bank entity have multivalued attribute(phone),in relational model we can't store multiple values for single attribute. So we need to create one more table to store phone numbers, with one more attribute which reference the one of attribute uniquely indentifies the rows in bank table. ex: phonenumbers(code,phone); So Total minimum tables are 4. 0 votes 0 votes Verma Ashish commented Nov 25, 2019 reply Follow Share @Satbir here in top answer and in above comment by bikram sir.. most of them saying that 1 table.. i am not understanding why? Multivalued attributes should not be there for 1 nf also ..right? so we need two tables 0 votes 0 votes Satbir commented Nov 25, 2019 reply Follow Share we made 2 tables one normal and one for multivalue attribute. After doing this we can merge them into a single table . creating tables from Er daigram are by default in 1 NF 2 votes 2 votes Please log in or register to add a comment.
11 votes 11 votes There is only one condition that needs to be fulfilled in 1NF that all values should be atomic no other constraint 1 table is enough. Every 1 NF can be brought under 1 table Tesla! answered Sep 19, 2017 Tesla! comment Share Follow See all 14 Comments See all 14 14 Comments reply Show 11 previous comments Shivansh Gupta commented Dec 14, 2017 reply Follow Share @Tesla, There is only one condition that needs to be fulfilled in 1NF that all values should be atomic no other constraint What will be the answer for 2 Entities related by a M:N relationship ? Can they also be brought under 1 table? 1 votes 1 votes Tesla! commented Dec 14, 2017 reply Follow Share Yes if you want 1 NF then it doesn't matter how much complicated table is it can be brought under 1 table. 1 votes 1 votes Shivansh Gupta commented Dec 15, 2017 reply Follow Share Redundancy or no redundancy, a relational table must be a valid relational table first, i.e. each entity in the relation must be accessible through some key. If that is not possible, then no point of 1NF, 2NF, 3NF, etc. 0 votes 0 votes Please log in or register to add a comment.
5 votes 5 votes $4$ tables. {Ph_No} {Branches, Bank Branch} {Bank} { Loan, Loans } Aghori answered Aug 11, 2017 Aghori comment Share Follow See all 15 Comments See all 15 15 Comments reply Show 12 previous comments Aghori commented Aug 27, 2017 reply Follow Share @reena_kandari Phone_no is multivalued attribute. If you break it without making an extra table you will have to generate 1 or more columns/attributes like Phone_no2, P_No3 etc ( based on the cardinality of multivaluedness of the column) which are not present in the original ER diagram. This ER diagram has only 1 attribute which is Phone_no. 0 votes 0 votes set2018 commented Sep 11, 2017 reply Follow Share @Aghori https://gateoverflow.in/3717/gate2004-it-73 for 1 nf it should be 3 table right ? 1 votes 1 votes reena_kandari commented Oct 15, 2017 reply Follow Share @set2018 && @aghori for 1 NF you can merge Multivalued attribute in one single table but here you can't do it bcz if you merge it then PK of BANK will be will {Code,phone no} and in BANK_BRANCH there is FK {code} which refers to PK of BANK, but only {Code} is not the PK of this table so you have to keep a separate table for {phone_no} here..Hence we come up with 4 tables here. 2 votes 2 votes Please log in or register to add a comment.
4 votes 4 votes 4 tables are required 1.Bank(Code,Name,Address) 2. For multivalued attribute(Ph_No,Code) 3.Bank Branch(Addr,Branch_No,Code,Bank Name) 4.Loan(Loan_no,Amount,Type,Branch_no) atul_21 answered Aug 12, 2017 atul_21 comment Share Follow See all 0 reply Please log in or register to add a comment.
1 votes 1 votes As phone number is multivalued attribute there should be one table for it. Now Loan and the Loans can be combined into a single table as the relationship Loans is many-to-one relationship and participation is total in many side.There should be another one table. Now there will be only one table needed for Bank,Branches and Bank Account.Because there is full participation between entities in the relationship. So three tables should be there.But the question mentioned 1NF so we can combine these three tables into 1 table.So the final answer will be one I think. debasish paramanik answered Aug 23, 2020 debasish paramanik comment Share Follow See 1 comment See all 1 1 comment reply shashankpal commented Aug 24, 2020 reply Follow Share See that's why I'm confused. Everyone is saying 4 tables, I thought 3 and you've also said 3 tables. As we can combine bank branch and bank into one due to total participation and have primary key of bank branch as the primary key of this whole relation as its many. So aside from this 1nf debacle, what would be the correct answer 3 or 4?. If we're considering separate tables for multivalued attributes. 0 votes 0 votes Please log in or register to add a comment.