I keep encountering situations where all the business logic for the
applications is in stored procedures and the application layer is just calling
the stored procedures to get the work done and return the data. There are many
problems with this approach some of them are.
Replica sets is a feature of MongoDB for Automatic Failover, in this setup there is a primary server and the rest are secondary servers. If the primary server goes down, the rest of the secondary servers choose a new primary via an election process, each server can also be assigned number of votes, so that you can decide the next primary based on data-center location, machine properties etc, you can also start mongo database processes that act only as election tie-breakers these are known as…
Dead lock is caused in the database when you have resources (connections) waiting for other connections to release locks on the rows that are needed by the session, resulting in all session being blocked. Oracle automatically detects deadlocks are resolves the deadlock by rolling back the statement in the transaction that detected the deadlock. Thing to remember is that last statement is rolled back and not the whole transaction, which means that if you had other modifications, those rows are…!-->!-->
Oracle has metadata about all its objects in various tables/views. One such view is the USER_OBJECTS or ALL_OBJECTS, this view has a column named as STATUS which shows you if the given object is VALID or INVALID. The status applies to DB Code (Stored Procedures, Functions, Triggers etc).
We came across a need to save just the Time in the database, the requirement is to store time of the day, like say the user likes to have Breakfast at 8.15AM and Lunch at 12.32PM etc. Off course oracle does not have a time only data type. So we ended up using DATE as the data type and just setting the time. for example:
Some environments like to have access to the database tables routed via stored procedures.
Instead of using Create/Read/Update/Delete (CRUD) with DML, stored procedures are invoked with the parameters to perform the required operation. I'm not arguing about the benefits/pitfalls of this approach, if you have to do stored procedures, here are some things to look at.
Couple of weeks back I was given a choice to upgrade my work Laptop to a Mac Book Pro or a Windows Laptop. I choose Mac ( I know everyone is into macs nowadays). The transition was pretty good, with the exception of moving my oracle database from windows to mac, since there is no native installation of oracle on mac I had to use VMWare fusion to install oracle.
When creating a Foreign Key constraint on the database as shown below
We had a weird requirement on our project recently..
When doing Performance Testing or running Unit/Functional tests on a database, there is a need to periodically get the database to a known state, so that the tests behave in a predictable way and to get rid of all the data created by the tests. Some of the ways to get a clean database are.