Posts Tagged ‘Database’

How To Convert Number into Words using Oracle SQL Query

How To Convert Number into Words using Oracle SQL Query
How can you convert a number into words using Oracle Sql Query? What I mean by Number to Word is:Here's a classy query which will convert number into words.Please see the query below:select to_char(to_date(:number,'j'),'jsp') from dual;If I pass 234 in number, then the output will : two hundred thirty-fourSELECT TO_CHAR (TO_DATE (234, 'j'), 'jsp') ...

Spring Roo: Two Databases Configuration

Spring Roo: Two Databases Configuration
I've seen very often a recurrent question on Spring Roo forums. The question is "How to configure the application to handle two databases".Certainly this is a more ample question to Spring Roo only, due it involves JPA and the Spring persistence stack. So, I believe it will be of interest to all the Spring development community ...

Row Data Multiplication in Oracle

Row Data Multiplication in Oracle
Aggregate functions return a single result row based on a group of rows. This differentiates them from Single-Row functions which act on each row. These functions are extensively used with the GROUP BY clause in SQL statements. AVG (), COUNT (), SUM () ... are few aggregate functions which are quite commonly used. Today, one ...

Generating Random Data in Oracle

Most of the times, production data is not available in development environments. Here, I would like to share a single sql command which can generate random data. But before that, let's address another issue faced by a lot of new oracle users. We need to generate a sequence of numbers using a sql statement. This will generate a number sequence. ...

Deleting Duplicate Rows in Oracle

Deleting Duplicate Rows in Oracle
Deleting duplicate rows from tables is one of the common task oracle developers come across. The data might get duplicated because of missing primary/unique key on the table or batch file getting loaded multiple times. Here I have tried to summarize different ways of deleting this duplicated data. Please note that this is not an extensive list ...

Invisible Indexes in Oracle 11g

Invisible Indexes in Oracle 11g
The effective usage of an index is always a big question. There are instances in production environments, where an index may help the performance of just a single query, while it can degrade the performance of a number of queries. Always the Optimizer can’t guarantee the best suitable index required for the query in an environment ...

Oracle Data Compression

Oracle Data Compression
As the data grows in relational databases (new business requirements, managing audit data etc), the cost associated with the disk systems to store that data and the resources required to manage them becomes vital. Oracle understands this requirement and it is continuously implementing and improving on the compression techniques and algorithms while simultaneously meeting the application scalability ...

Understanding Primary Key(PK) Constraint in Oracle

Understanding Primary Key(PK) Constraint in Oracle
The Primary Key(PK) constraint is the most basic concept of any RDBMS (I am particularly interested in Oracle). Yet, I have noticed people getting confused when it comes to the practical usage and asking questions like:- I have disabled PK and now oracle is doing full table scan. - How PK constraints and indexes are related/different? - How ...

Fast data copy with “Create Table Select From” in PL/SQL

Fast data copy with
Although I work mainly in Java/J2EE, recently I had a requirement in Oracle to take temporary backup of a table and compare the data of original table with this backup table. So I had to copy the data from table A to a temp table TA.First I tried creating temp table normally and copied the ...

Fetch Random rows from Database (MySQL, Oracle, MS SQL, PostgreSQL)

Fetch Random rows from Database (MySQL, Oracle, MS SQL, PostgreSQL)
Ever thought why would one need to fetch random rows from a database table? You may want to display some random information (like articles/pages/links) to your user. I had a requirement wherein I had to fetch 10 random rows from MySQL database and display it on screen. I used following simple query for retrieving random records ...
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