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  CASSANDRA data model

Cassandra is an open source distributed database, it combines dynamic key/value and column oriented feature of Bigtable. Features of Cassandra are: Flexible schema, no need to design schema first, it's very convenient to add or delete strings Support range search on keys High usability, extensible. The single node error will not affect the cluster. We can think Cassandra's data model as a 4 or 5 dimensional Hash. COLUMN Columns is the smallest data unit in Cassandra, it is a 3 dimensional data...

1,419 0 0          DATABASE SORT CASSANDRA


  SQLite C/C++ function interfaces

Some simple introduction to the SQLite function interfaces. First let's check some error codes defined in SQLite3 (They are in SQLite3.h file in the SQLite installation).#define SQLITE_OK           0   /* Successful result */  /* beginning-of-error-codes */  #define SQLITE_ERROR        1   /* SQL error or missing database */  #define SQLITE_INTERNAL     2&nb...

2,140 0 0          SQLITE FUNCTION INTERFACE C/C++


  Three things you should never put in your database

As I've said in a few talks, the best way to improve your systems is by first not doing "dumb things". I don't mean you or your development staff is "dumb", it's easy to overlook the implications of these types of decisions and not realize how bad they are for maintainability let alone scaling. As a consultant I see this stuff all of the time and I have yet to ever see it work out well for anyone. Images, files, and binary data Your database supports BLOBs so it must be a good idea to shove ...

1,667 0 0          DATABASE IMAGE LOG BLOB


  11 Important Database designing rules

Introduction Before you start reading this article let me confirm that I am not a guru in database designing. The below 11 points which are listed are points which I have learnt via projects, my own experiences and my own reading. I personally think it has helped me a lot when it comes to DB designing. Any criticism welcome. The reason why I am writing a full blown article is, when developers sit for designing a database they tend to follow the three normal forms like a silver bullet. They...

1,919 0 0          RULES DATABASE DESIGN OLAP


  Introducing LocalDB, an improved SQL Express

Updated 2011-11-28: Added reference to the walkthrough of using LocalDB in Visual Studio 2010 and to the new LocalDB Installer. Updated 2011-11-02: Added reference to .NET Framework 4 support for LocalDB in the Q&A section. Introduction It gives me great pleasure to introduce a new version of SQL Express called SQL Express LocalDB. LocalDB is created specifically for developers. It is very easy to install and requires no management, yet it offers the same T-SQL language, programming surfac...

4,282 0 0          MICROSOFT LOCALDB SQL EXPRESS


  20 Database Design Best Practices

Use well defined and consistent names for tables and columns (e.g. School, StudentCourse, CourseID ...).Use singular for table names (i.e. use StudentCourse instead of StudentCourses). Table represents a collection of entities, there is no need for plural names.Don’t use spaces for table names. Otherwise you will have to use ‘{‘, ‘[‘, ‘“’ etc. characters to define tables (i.e. for accesing table Student Course you'll write “Student Course”. StudentCourse is much better)....

2,009 0 0          DESIGN PATTERN DATABASE DESIGN 20 TIPS WELL DEFINED NAME


  Why are column oriented databases so much faster than row oriented databases?

I have been playing around with Hybrid Word Aligned Bitmaps for a few weeks now, and they turn out to be a rather remarkable data structure.  I believe that they are utilized extensively in modern column oriented databases such as Vertica and MonetDB. Essentially HWABs are a data structure that allows you to represent a sparse bitmap (series of 0's and 1's) really efficiently in memory.  The key trick here is the use of run length encoding to compress the bitmap into fe...

1,804 0 0          DATABASE COLUMN ORIENTED SPEED ANALYSIS VERTICA


  Removing duplicates in sql

In modern web development, it’s standard practice to make use of a database abstraction layer, typically an Object-Relational Mapper based on either the Active Record pattern or the Data Mapper pattern. There are several pros and cons to this which are fairly well established, so I’ll spare us all from enumerating them all right now. One established pro worth mentioning is that these systems typically provide a high level interface for fetching data, often removing the need to ‘hand wr...

1,794 0 0          SQL WEB DESIGN DUPLICATE REMOVE