Can anyone help me understand if a table in a relational database (such as MySQL) can be without a primary key? For example, I could have table day_temperature, where I register temperature and time. I don't see the reason to have a primary key for such a table. Thoughts? Thanks, Boda Cydo. ...
I just found some strange behavior of database's "order by" clause. In string comparison, I expected some characters such as '[' and '_' are greater than latin characters/digits such as 'I' or '2' considering their orders in the ASCII table. However, the sorting results from database's "order by" clause is different with my expectation. ...
I want to list all users with their corropsonding user class. Here are simplified versions of my tables CREATE TABLE users ( user_id INT NOT NULL AUTO_INCREMENT, user_class VARCHAR(100), PRIMARY KEY (user_id) ); INSERT INTO users VALUES (1, '1'), (2, '2'), (3, '1,2'); CREATE TABLE classes ( class_id INT NOT N...
Hello! I have a table with all U.S. zip codes. each row contains the city and state name for the zip code. I'm trying to get a list of cities that show up in multiple states. This wouldn't be a problem if there weren't X amount of zip codes in the same city... So basically, I just want to the city in a state to count as 1 instead of ...
Electronic Medical records are composed of different types of data. Visit information ( date/location/insurance info) seems to lend itself to a RDMS. Other types of medical infomation, such as lab reports, x-rays, photos, and electronic signatures, are document based and would seem to be a good candidate for a 'document-oriented' datab...
I'm the process of moving applications over from all in the public schema to each having their own schema. for each application, I have a small script that will create the schema and then create the tables,functions,etc... to that schema. Is there anyway to automatically add a newly created schema to the search_path? Currently, the on...
Hi everyone, I want to know how can I perform VS2008 load test from five different machines and store test results data into one place, for example one database. It is load test that test unit test. I specify scenario and counter sets and I get result and reports that I can save as .trx files. How can I save specific data from test r...
Is there a way to keep 2 sequences synchronized in Postgres? I mean if I have: table_A_id_seq = 1 table_B_id_seq = 1 if I execute SELECT nextval('table_A_id_seq'::regclass) I want that table_B_id_seq takes the same value of table_A_id_seq and obviously it must be the same on the other side. I need 2 different sequences because I ...
We have a project coming up where we will be building a whole backend CMS system that will power our entire extranet and intranet with one package. The question I have been trying to find an answer to is which is better: storing images in the database (SQL Server 2005) so we may have integrity, single replication plan, etc OR storing on ...
This has been a big question mark on my mind. I'm moving to Mercurial or Git very soon for my web software, and sometimes my branches require significant database changes which other branches should not see. This, I can't always share the same database for my branches. Is there some standard way of dealing with database changes for bra...
i do export of an tablespace. This tablespace contains table1 with two rows say rowa and rowb/ now i delete rowb and insert new rowc into this tablespace. Now i do import of this tablespace. after importing i see the table1 in tablespace contains rowa, rowb,rowc but it was suppose to contain rowa and rowb. Can anybody tell why is thi...
TLDR: What are the pros/cons of using an in-memory database vs locks and concurrent data structures? I am currently working on an application that has many (possibly remote) displays that collect live data from multiple data sources and renders them on screen in real time. One of the other developers have suggested the use of an in mem...
I am using Oracle 9i and want to know to the definition(code) of predefined functions in Oracle like,REVERSE(),REPLACE(). Is there any library of oracle where i can serach these library functions! Please Suggest!! ...
Lets say I have the following MySQL structure: CREATE TABLE `domains` ( `id` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT, `domain` CHAR(50) NOT NULL, `parent` INT(11) DEFAULT NULL, PRIMARY KEY (`id`) ) ENGINE=MYISAM AUTO_INCREMENT=10 DEFAULT CHARSET=latin1 insert into `domains`(`id`,`domain`,`parent`) values (1,'.com',0); insert into `d...
Hi. What is the best way to store a list of random numbers (like lotto/bingo numbers) and retrieve them? I'd like to store on a Database a number of rows, where each row contains 5-10 numbers ranging from 0 to 90. I will store a big number of those rows. What I'd like to be able is to retrieve the rows that have at least X number in comm...
I'm trying to perform an integration test via Watir and RSpec. So, I created a test file within /integration and wrote a test, which adds a test user into a base via factory_girl. The problem is — I can't actually perform a login with my test user. The test I wrote looks as following: ... before(:each) @user = Factory(:user) @brow...
When mapping an object using SQLAlchemy, is there a way to only map certain elements of a class to a database, or does it have to be a 1:1 mapping? Example: class User(object): def __init__(self, name, username, password, year_of_birth): self.name = name self.username = username self.password = password ...
I have a checkboxes on my site that when unchecked, update their row in in the db as unchecked, and if checked,update their row in the db as checked. I am creating an ifstatement that will commence with its command if checked, and not if unchecked. I have echoed the variable and it is holding the proper value (checked or unchecked) but n...
I'm working with EJB and JPA on a Glassfish v3 app server. I have an Entity class where I'm forcing one of the fields to be unique with a @Column annotation. @Entity public class MyEntity implements Serializable { private String uniqueName; public MyEntity() { } @Column(unique = true, nullable = false) public Str...
I was wondering if there is a nice IF NOT EXISTS for checking columns and indexes in SQLite, or do I need to bring back the entire database schema and validate against that? ...