database-normalization

I have these tables: Projects(projectID, CreatedByID) Employees(empID,depID) Departments(depID,OfficeID) Offices(officeID) CreatedByID is a foreign key for Employees . I have a query that runs for almost every page load. Is it bad practice to just add a redundant OfficeID column to Projects to eliminate the three joins? Or should I do the following: SELECT * FROM Projects P JOIN Employees E ON P.CreatedBY = E.EmpID JOIN Departments D ON E.DepID = D.DepID JOIN Offices O ON D.officeID = O.officeID WHERE O.officeID = @SomeOfficeID In application programming I "Write with best practices first and

Background I'm a first year CS student and I work part time for my dad's small business. I don't have any experience in real world application development. I have written scripts in Python, some coursework in C, but nothing like this. My dad has a small training business and currently all classes are scheduled, recorded and followed up via an external web application. There is an export/"reports" feature but it is very generic and we need specific reports. We don't have access to the actual database to run the queries. I've been asked to set up a custom reporting system. My idea is to create

I have one table. How can I normalize this. Good question given your data set. Keep in mind the whole point of normalization is to reduce duplication. 3NF is often the best way to go. But given my experience I've found very little benefit to pulling a repeated value out into a different table if it will be the only value in that table. Take for example your most duplicated column, emp_type. If you were to normalize it into a separate table , it would look like this: Emp_Type_Id | Emp_type ------------------------ 1 | Manager 2 | Engineer 3 | Tech Support And your current table would look like:

I'm a bit confused about a certain piece of database normalization and thought I'd ask StackOverflow: Imagine you have the following relations that relate products to colors. Notice that Product 1 and Product 2 both use the same set of colors (Blue and Green). Product_Color Color +-------------+-------------+ +-------------+-------------+ | Product* | Color* | | ColorId* | Name | +-------------+-------------+ +-------------+-------------+ | 1 | 1 | | 1 | Blue | | 1 | 2 | | 2 | Green | | 2 | 1 | +-------------+-------------+ | 2 | 2 | +-------------+-------------+ If I create two new relations,

In MySQL 5.7 a new data type for storing JSON data in MySQL tables has been added. It will obviously be a great change in MySQL. They listed some benefits Document Validation - Only valid JSON documents can be stored in a JSON column, so you get automatic validation of your data. Efficient Access - More importantly, when you store a JSON document in a JSON column, it is not stored as a plain text value. Instead, it is stored in an optimized binary format that allows for quicker access to object members and array elements. Performance - Improve your query performance by creating indexes on

Consider the relation R(A, B, C, D, E, F, G) with the following types of attributes:- Total No of Keys = 1 = {A} Set of Simple (or) Atomic (or) Single Valued Attributes = {B, C} Set of Multivalued Attributes = {D, E} Set of Composite Attributes = { F, G} What would be the minimum no of tables that exists after decomposing relation R into 1NF? (A) 3 (B) 2 (C) 4 (D) 5 My attempt: We needed different table for each multivalued attributes with given key(A), total = 2 Similarly, we needed different table for each composite attributes, total = 2. There are total 4 such attribute. I give 4 tables