I have two tables, products and categories which have a many to many relationship, so I'm adding a products_categories table which will contain category_id and product_id. Should I add another (autoincrementing) index column or use the two existing ones as primary key? ...
I am working for a company and I need to create a program really fast. My program will run with 100 users and they will make approximately 100 transactions each per day. As I am under time pressure, and various other constraints it is not possible to set up a proper database running on a server. I am therefore looking for alternatives th...
Hi all, Are there any performance gains in using stored procedures for simple SQL inserts into tables over using direct SQL from java / JDBC? in my case I am using sybase but this could be a more general question. Thanks ...
I've looked through all the "related questions" with two or three different titles and didn't see anything, so here goes. I've used SQL Server and Oracle in the recent past at work. I want to futz around at home, mostly with Java, perhaps with Ruby on Rails or Python. I'm running Windows 7. I usually make web applications, might like...
Just a simple question, but does the order of your index matter when it spans over multiple columns? For example, taking the query: SELECT * FROM my_table WHERE (column_1 = 1 AND column_2 = 2) If I want to add an index for a query like this, does it matter if my index is created like this: CREATE INDEX my_index ON my_table (column...
currently we are developing an app in which we use database table to store platform settings, like maximum file size, maximum users number, support email, etc. it means that each time we add a platform setting we have to add a column to this table. in my previous projects i am used to store such information in file. what is better/fa...
Imagine you're dealing with many strings of text that are about 10,000 characters long entered by users. Would it be more efficient to write those automatically onto pages or input them onto a table in a database? I hope that question is clear enough... ...
Hi! I'm trying to find a way to match a query to a regular expression in a database. As far as I can tell (although I'm no expert), while most DBMS like MySQL have a regex option for searching, you can only do something like: Find all rows in Column 1 that match the regex in my query. What I want to be able to do is the opposite, i.e.:...
specialcharacters åöö in the database cant be shown when i retrieve the rows and echo it. what can i do to have them shown propertly? ...
im coding a guestbook and i want new lines and spaces to be shown when i show the posts? when i post a thread now everything is shown on one line. help! ...
I need to copy over rows from Table B to Table A. The requirement is to only insert rows that are not already in A. My question is, which is of the the following two is more efficient: A) INSERT INTO A (x, y, z) SELECT x, y, z FROM B b WHERE b.id NOT IN (SELECT id FROM A); B) INSERT INTO A (x, y, z) SELECT b.x, b....
Hi, A very naive question. I need to store currency in the database. Both the value and the code. To solve this, do people generally make 2 columns, one storing the value and other the code? Or is there an inbuilt type I can use? -thanks ...
This is probably a really stupid question, but is there going to be much benefit in indexing a boolean field in a database table? Given a common situation, like "soft-delete" records which are flagged as inactive, and hence most queries include WHERE deleted = 0, would it help to have that field indexed on its own, or should it be combi...
We are going to develop a new system over a legacy database(using .NET C#).There are approximately 500 tables. We have choosen to use an ORM tool for our data access layer. The problem is with namig convention for the entities. The tables in the database have names like TB_CUST - table with customer data, or TP_COMP_CARS - company cars....
Hi, all I want to use an example to explain what I want. Assume I've following DB design: Item (id, name, categoryID); Category (id, name); When user wants to create an Item (fill in form), I'll give a list of categories in a dropdownlist, and when user chooses one of the categories ASP.NET MVC will automatically bind categoryID, to...
I have a Mysql database of 500+ Real Estate Listings which I am looking to load into an empty Joomla Extension (this may apply to any PHP Script). I have copied the structure and convention of each table the extension uses - with the idea of either exporting or simply deleting the original tables and replacing them with mine. Upon test...
I'm working in JDeveloper and I need to connect to Oracle Database using the ApplicationModule interface. So I set up the connection, imported the table and created a view. Then I created a new ApplicationModuleImpl that connects to that view. Now, how do I get to the data through the ApplicationModule object? I read the documentation ...
Is it possible to do Table Inheritance in Java DB? We have a complex code model that uses inheritance and would also benefit from DB inheritance. Is it possible? It doesn't seem possible from a quick google or a poke around in netbeans. Cheers ...
Hai I am preparing for DBMS exam where i want to calculate the memory size (in bytes) occupied by the B+tree. thank u. ...
I am trying to implement a Faceted search or tagging with multiple-tag filtering. In the faceted navigation, only not-empty categories are displayed and the number of items in the category that are also matching already applied criteria is presented in parenthesis. I can get all items having assigned categories using INNER JOINs and ge...