diff --git a/README.md b/README.md index c89e9fd..a7257f5 100644 --- a/README.md +++ b/README.md @@ -1,29 +1,13 @@ # DBNormalizer Minimal command line python program to help you normalise your relational database design. -## Before you Run: -Modify the portion indicated in the main.py file according to comment (YES pls modify inside the source code). -The modification basically gives the following inputs: -1. Set of variables in your database. -2. List of functional dependencies implied in your database (You don't have to list trivial ones). -3. Set the normal form you want to test/achieve. - -An example of the inputs will be: -``` -R = ['A','B', 'C'] -FD = [ - [['A', 'B'], ['C']], - [['A'], ['B']], - [['B'], ['A']] -] -normalform = normalforms.threenf -``` - ## How to Run: -python main.py +`python main.py` + +The program will prompt you to enter the **attributes**, **FDs** and the **normal form type**. ## Output: -(Note: Output is formated using python3. For best experience pls use python3.) +(Note: Output is formatted using python3. For best experience pls use python3.) Following the previous example, the output will be: ``` @@ -62,9 +46,9 @@ already in 3NF * The 1st section gives you all possible candidate keys * The 2nd section computes the minimal cover * The 3rd section checks if the supplied functional dependencies are normalized. -* The 4th section trys to achieve required normalization by decomposition method (can loose some dependencies). -* The 5th section trys to achieve 3NF by synthesis method (only 3NF is guaranteed, and all dependencies preserved). +* The 4th section tries to achieve required normalization by the decomposition method (can lose some dependencies). +* The 5th section tries to achieve 3NF by synthesis method (only 3NF is guaranteed, and all dependencies preserved). -Unless you must achieve BCNF, synthesis method is more popular because it at least gives you 3NF and preserves +Unless you must achieve BCNF, the synthesis method is more popular because it at least gives you 3NF and preserves all original dependencies. And mostly likely, it gives you BCNF as well. diff --git a/main.py b/main.py index d2d8dfe..c21f47a 100644 --- a/main.py +++ b/main.py @@ -17,15 +17,38 @@ ########################################### # Modify from this line onwards to suit your needs -R = ['A', 'B', 'C'] -FD = [[['A', 'B'], ['C']], [['A'], ['B']], [['B'], ['A']]] -normalform = normalforms.threenf + +R = input("Enter the list of unique variables of R separated by commas (e.g. a,b,c,d): ").split(",") +FD = [] +while True: + dep = input("Enter a functional dependency (e.g. a,b->c) or enter nothing to stop: ") + if not dep: + break + try: + lhs, rhs = dep.split("->") + FD.append([lhs.split(","), rhs.split(",")]) + except ValueError: + print("Invalid functional dependency! Reenter the functional dependency.") +while True: + normalform_name = input("Enter the normal form you want to achieve (2nf, 3nf, or bcnf): ") + if normalform_name == "2nf": + normalform = normalforms.twonf + break + elif normalform_name == "3nf": + normalform = normalforms.threenf + break + elif normalform_name == "bcnf": + normalform = normalforms.bcnf + break + else: + print("Invalid normal form! Reenter the normal form.") + # Do not modify anything from this line onwards ########################################### # find all candidate keys ########################################### -print('all candiate keys:') +print('all candidate keys:') print(api.candidate_keys(R, FD)) ########################################### @@ -34,46 +57,43 @@ print('') print('') print('a minimal cover:') -minCover = api.min_cover(R,FD) +minCover = api.min_cover(R, FD) for F in minCover: - print(F[0],'->',F[1]) + print(F[0], '->', F[1]) ########################################### # check all F in FD for violation of given normal form ########################################### print('') -print('') -print('check normal form:',normalform.__name__) -FDsimplified = api.min_cover_step1(R,FD) +print('') +print('check normal form:', normalform.__name__) +FDsimplified = api.min_cover_step1(R, FD) for F in FDsimplified: - print(F[0],'->',F[1],normalform(R,FDsimplified,F)) - + print(F[0], '->', F[1], normalform(R, FDsimplified, F)) ########################################### # decomposition to given normal form -# also check wether decomposition is dependency-preserving +# also check whether decomposition is dependency-preserving # if not show which dependency is lost # also verify result against given normal form ########################################### useSigmaPlus = True -printStep = False # if true will print steps invovled in deriving the answer +printStep = False # if true will print steps involved in deriving the answer print('') print('') -print('decomposition:',normalform.__name__, 'showStep' if printStep else '') -fragments = decomposition.decompose(R,FD,normalform,useSigmaPlus,printStep) -decomposition.print_fragments(fragments,normalform) +print('decomposition:', normalform.__name__, 'showStep' if printStep else '') +fragments = decomposition.decompose(R, FD, normalform, useSigmaPlus, printStep) +decomposition.print_fragments(fragments, normalform) ########################################### # synthesize to 3NF (not any form) -# also check wether synthesize is dependency-preserving +# also check whether synthesize is dependency-preserving # if not show which dependency is lost # also verify result against 3NF ########################################### -printStep = False # if true will print steps invovled in deriving the answer +printStep = False # if true will print steps involved in deriving the answer print('') print('') print('synthesis: threenf', 'showStep' if printStep else '') -fragments = decomposition.simple_synthesis(R,FD,printStep) -decomposition.print_fragments(fragments,normalform) - - +fragments = decomposition.simple_synthesis(R, FD, printStep) +decomposition.print_fragments(fragments, normalform)