data-modeling

I have two databases in MySQL that already have data. they have exactly the same schema. I would like to merge those two databases into one only. I tried: mysqldump -u root -p --databases database1 database2 database3 > database1_database2_da However, when I try to open database1_database2_da , I only end up with data from one of the database, but not all of them. I also want to mention that the two databases have their records starting at 1, since they are automatically generated. Do you think there is a way to merge those two databases without losing data from any of them? Run mysqldump on

I am designing a basic inventory system for a vendor. They have many different product categories. Each product category has many different properties. A - x1, x2, x3, a1, a2, a3; B - x1, x2, x3, b1, b2, b3, b4; C - x1, x2, x3, c1, c2; Laptop - Make, Price, Quantity, Processor, OS, Hard drive, Memory, Video Card etc Monitor - Make, Price, Quantity, Size, ContrastRatio, Resolution etc Server - Make, Price, Quantity, Processor, OS, Memory, Netowrking etc Design1: Different tables for each category. Design2: Common Table, property table. What is the best approach? Definitely don't want to

I'm developing a simple survey module for an ASP application I'm working on and I'd like to get some suggestions on the data model. Questions can be one of three types - multiple choice, multiple answer; multiple choice, single answer, and free response. I'm thinking of the following tables: Question - with a question type discriminator ifeld PossibleAnswers- with a questionID and answer text field SurveyQuestionResponse- with a questionID, a clientID, and answer text Am I making this too simple? mjv Take a look at the Data Model library at databaseanswers.org Models #76 thru #81 seem

I am trying to learn Cassandra and always find the best way is to start with creating a very simple and small application. Hence I am creating a basic messaging application which will use Cassandra as the back-end. I would like to do the following: User will create an account with a username, email, and password. The email and the password can be changed at anytime. The user can add another user as their contact. The user would add a contact by searching their username or email. The contacts don't need to be mutual meaning if I add a user they are my contact, I don't need to wait for them to

I am writing a web application, that is US specific, so the format that other countries use for postal codes are not important. I have a list of us zip codes that i am trying to load into a database table that includes the 5 digit us zip code latitude longitude usps classification code state code city the zip code is the primary key as it is what i will be querying against. i started using a medium int 5 but that truncates the zip codes that have leading zeros. i considered using a char5 but am concerned about the performance hit of indexing against a char variable. so my question is what is

I have a subclass of NSManagedObject (NSMO) called Team. Team has a one to many relationship with another NSMO subclass called Contract. Contract has a 1-to-1 with Player (another NSMO). I would like to simplify my code that uses Team and be able to just refer to its "players". Players will just be an array of players that have a contract with a given team. I've tried creating a fetched property called players in XCode's data modeling tool with little success. I've tried many different approaches, but the one that makes the most sense is to name it "players", have the destination as Player and