Apparently the reason for the BigTable architecture has to do with the difficulty scaling relational databases when you're dealing with the massive number of servers that Google has to deal with. But technically speaking what exactly makes it difficult for relational databases to scale? In the enterprise data centers of large corporat...
I'm trying to connect the values of two join tables that I have and show the results based on a conditional relationship...and i'm having some problems I have a Users Model(:name, :password, :email), and Events model(:name, :etc) and Interests model (:name) I created about 5 records in each model. Then I created two join tables -> Use...
I've been working on this for a while now and I cant seem to find where there error. I have a User Model(:name, :password, :email), and Event model(:name, :etc) and Interest model (:name) [>all singular<] Then I created two join tables -> UsersInterests and EventsInterests; each not containing a primary key and only comprised of the us...
I have a User Model(:name, :password, :email), and Event model(:name, :etc) and Interest model (:name) [>all singular<] Then I created two join tables -> UsersInterests and EventsInterests; each not containing a primary key and only comprised of the user_id/interest_id and event_id/interest_id respectively. [>plural<] My Models Use the...
There're quite a few posts discussing relations vs document databases, however they are all quite generic. I'd like to understand their differences in a specific example. Let's imagine we're building another scrum-oriented project management web app. While we'd like to experiment with a new technology, we don't want to sacrifice desig...
I am looking for how to build a relational mysql database, and I would like to follow a tutorial. I need one that shows how to make multiple tables, and link those together using an id. Which I can later use to grab relational data from the different tables. This is probably easy stuff, but I am just learning about databases. Thank...
How can I implement a large relational database schema on a key value store? The following are the requirements: 1) uses no stored procedures or special database vendor specific features 2) Uses indexes 3) Uses joins 4) Many complex types in tables (VARCHAR, INT, BLOB, etc) 5) Billions of records 6) Full text search 7) Timestampe...
Good day, I have been using Rails/Mysql for the past while but I have been hearing about Cassandra, MongoDB, CouchDB and other document-store DB/Non-relational databases. I'm planning to explore them later as they might be better alternative for scalability. I'm planning to start an application soon. Will it make a different with Rail...
In developing a shopping cart application I've found that I needed to save settings and configurations based on the administrator's preferences and requirements. This information can be anything from company information, Shipping account IDs, paypal API keys, notification preferences, etc. It seems highly inappropriate to create a table...
Often, when I need to store system properties like admin info, versions, and so on, I use a flat file (database.properties, init.properties, etc). This seems common in other programs that I see and use on a daily basis. Sometimes a flat file isn't ideal for a number of reasons. Deploying a web app to numerous clients often comes with ...
I'm vainly attempting to learn how to use object databases. In database textbooks the tradition seems to be to use the example of keeping track of students, courses and classes because it is so familiar and applicable. What would this example look like as an object database? The relational database would look something like Student ...
It has been recommended to me that I investigate Key/Value pair data systems to replace a relational database I have been using. What I am not quite understanding is how this improves efficiency of queries. From what I understand you are going to be throwing away a lot information that would help to make queries more efficient, by simpl...
I am going to start designing a web app shortly, and while I have lots of experience doing it in the SQL world, I have no idea what I need to take into consideration for doing so with the goal of migrating to GAE in the very near future. Alternatively, I could design the app for GAE from the start, and so in that case, what are the diff...
I have a small amount of experience using SVN on my development projects, and I have just as little experience with relational databases. I know the basic concepts like tables, and SQL statements, but I'm far from being an expert. What I'd like to know is if there are any generic version control type systems like SVN, but that work with...
Is it possible to listen to relation database update? For example, my web app want to send data update to client through Comet technology. I can have the program to poll the database periodically, but that would not be performant and scalable. If app can hood to a "event handler" of database, then app can get notification every time gi...
I have a database with two tables - let's call them Foo and Bar. Each foo may be related to any number of bars, and each bar may be related to any number of foos. I want to be able to retrieve, with one query, the foos that are associated with a certain bar, and the bars that are associated with a certain foo. My question is, what is th...
I'm currently using the following PHP code: // Get all subordinates $subords = array(); $supervisorID = $this->session->userdata('supervisor_id'); $result = $this->db->query(sprintf("SELECT * FROM users WHERE supervisor_id=%d AND id!=%d",$supervisorID, $supervisorID)); $user_list_query = 'user_id='.$supervisorID; ...
Suppose you have two sets of conceptual entities: MarketPriceDataSet which has multiple ForwardPriceEntries PoolPriceForecastDataSet which has multiple PoolPriceForecastEntry Both different child objects have near identical fields: ForwardPriceEntry has StartDate EndDate SimulationItemId ForwardPrice MarketPriceDataSetId (forei...
Hi! We're drawing up the database structure with the help of mySQL Workbench for a new app and the number of joins required to make a listing of the data is increasing drastically as the many-to-many relationships increases. The application will be quite read-heavy and have a couple of hundred thousand rows per table. The questions:...
I have this problem decomposing a relation schema into a set of schemas that are in 3NF. I have this relation schema: R= (A, B, C, D, E, F) With the following set F of functional dependencies: A → ABCDEF B → C D → E Can anyone help me out? ...