database-normalization

问题 Given a database system which deals with Staff, Customers and Suppliers, all of which have multiple possible phone numbers, how would you go about storing these numbers in a nice normalised way? I have a had a little think about and the logical way isn\'t jumping out at me. 回答1: In most cases . . . "Staff" always describes people. Some customers are people. Some customers are businesses (organizations). "Suppliers" are usually (always?) organizations. Staff can also be customers. Suppliers

问题 In relational database design, there is a concept of database normalization or simply normalization, which is a process of organizing columns (attributes) and tables (relations) to reduce data redundancy and improve data integrity. (as written on Wikipedia). As most articles are somewhat technical and thus harder to understand, I\'m asking for someone to write an easier to understand explanation based on examples about what 1NF, 2NF, 3NF, even 3.5NF (Boyce-Codd) mean. 回答1: 1NF is the most

问题 Could anybody help me to know what is normalization in mysql and in which case and how we need to use it.. Thanks in advance. 回答1: I try to attempt to explain normalization in layman terms here. First off, it is something that applies to relational database (Oracle, Access, MySQL) so it is not only for MySQL. Normalisation is about making sure each table has the only minimal fields and to get rid of dependencies. Imagine you have an employee record, and each employee belongs to a department.

问题 I have a relation in a database: Emp_project(SSN,PNum,Hours,Ename,PName,Plocs) I have been asked to normalize the relation Emp_project . How do I normalize it? 回答1: A relation has an associated set of columns of any type and an associated set of rows. There is one value per column per row. Sometimes "normalize" is used to mean (1) "decompose each relation to smaller relations that are its projections and that join back to it". This is normalization to higher NFs (normal forms) than 1NF. This

问题 Imagine a web form with a set of check boxes (any or all of them can be selected). I chose to save them in a comma separated list of values stored in one column of the database table. Now, I know that the correct solution would be to create a second table and properly normalize the database. It was quicker to implement the easy solution, and I wanted to have a proof-of-concept of that application quickly and without having to spend too much time on it. I thought the saved time and simpler