Why doesn't Oracle have foreign keys in Oracle Apps/ E-Business Suite? I observed that Oracle doesn't have/use referential constraints on the Oracle Apps 11i Schema. All the logic is contained in PL/SQL packages. This seems odd coming from a RDBMS major. ...
I'm not looking for a holy war here, I am thinking through a distributed architecture and would like input on How do I choose between a RDBMS vs. a DocDBMS? We cannot deny the power that can be had by using a RDBMS (i.e. MySQL, PostgreSQL, MS Sql Server, etc), they have been in development for more than 30 years and many issues have bee...
I'm archiving this web forum, which normally gets purged about once a week. So I'm screen scraping it, and storing it into my database (PostgreSQL). I also do a little analysis on the data, with some graphs for users to enjoy, like what time of day is the forum most active, and so forth. So I have a posts table, like so: Column |...
How does the data in a database in the field get upgraded because a new version of the software is being released? For an example, consider look up data. Usually the look up data associates an ID (number) to a name (string) and then this ID is referenced in other tables instead of the the ID directly (i.e. normalized). There are other ty...
My application includes a client, web tier (load balanced), application tier (load balanced), and database tier. The web tier exposes services to clients, and forwards calls onto the application tier. The application tier then executes queries against the database (using NHibernate) and returns the results. Data is mostly read, but writ...
EDIT I've just started skimming Codd's famous 1970 paper that started it all, that Oracle was based on (A Relational Model of Data for Large Shared Data Banks [pdf]), and was amazed to find that it seems it will answer this SO question. It talks about databases in the market at that time ("hierarchical" and "network" - like NoSQL?), the...
I have a migration which adds triggers to MySQL via invoking ActiveRecord::Base.connection() method "execute". It works fine except what schema version is not updated. I suspect that is because the DB structure by itself is not changed (no columns and table updates). Is there a way to force the schema version update in my migration? ...
I've volunteered with a Non-Governmental Organization to help with their record-keeping at their community centre. At present, there is only one community centre where all their data is stored. However, this is expected to change by the end of the year. Presently their data is maintained using a workbook with two sheets. Each record in ...
This is linked to my other question when to move from a spreadsheet to RDBMS Having decided to move to an RDBMS from an excel book, here is what I propose to do. The existing data is loosely structured across two sheets in a work-book. The first sheet contains main record. The second sheet allows additional data. My target DBMS is my...
This are few of the fundamental database questions which has always given me trouble. I have tried using google and wiki but I somehow I miss out on understanding the functionality rather than terminology. If possible would really appreciate if someone can share more insights on this questions using some visual representative examples....
I have a table in which I need both the values to be primary because I am referencing this combination as foreign key in the other tables. Table definition and the data I need to put are as follows create table T1 ( sno number(10), desc varchar2(10), constraint T1_PK primary key(sno,desc) ) DATA to put sno | desc -------------...
I have a table with two child tables. For each record in the parent table, I want one and only one record in one of the child tables -- not one in each, not none. How to I define that? Here's the backstory. Feel free to criticize this implementation, but please answer the question above, because this isn't the only time I've encountered...
Hi, I wonder if there is a canonical way to convert data from long to wide format in SQLite (is that operation usually in the domain of relational databases?). I tried to follow this example for MySQL but I guess SQLite does not have the same IF construct... Thanks! ...
I know implementing database is a huge topic, but I want to have a basic understanding of how database systems work (e.g. memory management, binary tree, transaction, sql parsing, multi-threading, partitions, etc) by investigating the source code of the database. Since there are a few already proven very robust open source databases li...
We typically interface with a RDBMS through SQL. I.e. we create a sql string and send it to the server through JDBC or ODBC or something similar. Are there any RDBMS that allow direct interfacing with the database engine through some API in Java, C#, C or similar? I would expect an API that allows constructs like this (in some arbitrary...
What is the best way of handling many-to-many relations in a RDBMS database like mySQL? Have tried using a pivot table to keep track of the relationships, but it leads to either one of the following: Normalization gets left behind Columns that is empty or null What approach have you taken in order to support many-to-many relationsh...
Hi I need some advice regarding multiple records. I have a table with fields username,*message* and message_to. the scenario could be of sending same message to multiple users in a go. What do you suggest? will it be efficient to save all recipients in a single column with comma separated values or I add multiple entries ? Thanks /A ...
A long time ago Joel explained how various every-day coding things were slow, and this led to XML as a data store being slow: Back to Basics Are those every-day coding things - strcat and malloc - still slow in a std::string and dlmalloc world? What else has changed in modern processors and mainstream frameworks? And is XML still slow...
Hi! I'm using a nested set in a MySQL table to describe a hierarchy of categories, and an additional table describing products. Category table; id name left right Products table; id categoryId name How can I retrieve the full path, containing all parent categories, of a product? I.e.: RootCategory > SubCategory 1 > SubCategory 2...
I'm considering storing the content of a web app in an RDF or OWL ontology instead of an RDBMS. However, when I research ontologies they seem to always exist in the context of publicly accessible data stores serving as the backbone of the semantic web. I've never heard of them being used as the content engine behind a web app. Is it re...