Hi I had 2 tables in Cache in web server. The size of tables is considerable huge. Each time to retrieve data I have to do a join on these 2 tables. Other option I have is have nothing in cache and making a db call each time that will do a join on the db tables. So what I want to know is doing a join on webserver is it costlier than...
How can I store logical expressions using a RDBMS? I tag objects and would like to be able to build truth statements based on those tags. (These might be considered as virtual tags.) Tags new for_sale used offer Rule second_hand_goods = (!new or used) and for_sale new_offer = new and offer second_hand_offer = second_hand_goods and of...
I am an experienced Java developer, used to all the nice features that Eclipse provides for Java development (in particular Ctrl+T to open type, Ctrl+Click or F3 to open referenced declaration, outline, ...). I really like this degree of comfort. Now I have a project, where I need to do some changes in the existing database (stored proc...
We currently have a search on our website that allows users to enter a date range. The page calls a stored procedure that queries for the date range and returns the appropriate data. However, a lot of our tables contain 30m to 60m rows. If a user entered a date range of a year (or some large range), the database would grind to a halt....
Hi All, I have a MySQL indexing question for you guys. I've got a very large table (~100Million Records) in MySQL that contains information about files. Most of the Queries I do on it involve substring operations on the file path column. Here's the table ddl: CREATE TABLE `filesystem_data`.`$tablename` ( `file_id` INT( 14 ) NOT...
We are in evaluating technologies that we'll use to store data that we gather during the analysis of C/C++ code. In the case of C++, the amount of data can be relatively large, ~20Mb per TU. After reading the following SO answer it made me consider that HDF5 might be a suitable technology for us to use. I was wondering if people here ...
Hi, I have the following situation, and I'd like to know what approach would you take to solve this problem. Here's the client needs. He needs a WebSite / E-Commerce and what to be able to customize the look of the e-commerce. He also wants to be able to extend some functionality like product configuration. He have an office in one co...
I have a database that uses natural keys (i.e. business oriented keys). Unfortunately, because of this, the primary keys for these objects may change over time. I am currently researching the use of NHibernate for an O/RM for this database. However, in my testing I have noticed that there is no apparent way to change the primary key of...
I'm a newbie in Database design and in Hibernate too. I started reading the documentation for Hibernate. It talked about "Collection Mapping", "Association Mapping" and "Component Mapping". I am not understanding the difference between them and not sure about when to use what in one-to-many/many-to-one/many-to-many relationships. To me, ...
I'm constantly hearing about person y had performance issue x which they solved through caching. Or, how doing x,y,z in your programs code can hurt your caching ability. Even in one of the latest podcasts, Jeff Atwood talks about how they cache certain values for speedy retrieval. There seems to be some ambiguity in the terms "cache" ...
How transaction should be handled while using Unit of Work pattern in a WinForm application Should new UOW session be created when form is initialized? Disposed when form is exited? call UOW.commit() in every save? Please advice Any articles on this topic?? ...
Hi, I'm a bit of a database novice, so pardon my naivety here. I have following sql statement: SELECT DISTINCT dbo.tb_user.familyName, dbo.user_email.email FROM dbo.tb_user INNER JOIN dbo.user_email ON (dbo.tb_user.id = dbo.user_email.userID) This returns records where an email address exists. What I would like to do is retrieve a...
I am using SQL Server for the first time and I see that a column property is called Is Identity. What doeds this mean? What are the advantages of marking a column property as Is Identity = Yes ? Thanks in advance. ...
I'm creating a program for end-users, that's already written using MySQL and some OpenOffice.org Star Basic Macros. I was wondering if there was an open source single user database that would be easy enough for the average Joe to install, (or that I could write a macro to install it for him...) ...
I need to have 2 or 3 synchronized sql database instances at different locations. Which of FREE databases can do that? ...
Hi Stackers After reading Bil Simser blog post Being a Better Developer... in 6 months I agree with his headlines which are: • Reading • Writing • Speaking • Community • Learning • Code, Code, Code and more code But I’ve a specific question "How to be a better database developer (specially Sql-Server developer)" and ...
I'm implementing a tag system similar to StackOverflow tag system. I was thinking about when storing the tags and relating to a question, that relationship will be directly with the tag name or it's better create a field tagID to "link" the question with the tag? Looks that linking directly to tag name is easier, but it doesn't look good...
I'm working on an AIR application that uses a local SQLite database and was wondering how I could manage database schema updates when I distribute new versions of the application. Also considering updates that skip some versions. E.g. instead of going from 1.0 to 1.1, going from 1.0 to 1.5. What technique would you recommend? ...
I have a stored procedure that takes a comma-delimited string of IDs. I split them and put them into a temporary table and pull out records from another table using where id IN [table] Is it ok to use this same procedure when only one id is passed in for the param? I could write a second stored procedure that would do exactly the sameth...
I like Active Record but many say it's bad in performance compared to Hibernate. There should be some good article out there but google can't help me. ...