When working with Chinese data in Oracle databases, character encoding issues often lead to garbled text, preventing proper display and processing. This is typically because the default character set in Oracle is US7ASCII, which cannot recognize Chinese characters. By modifying the character sets of the database, client, and application, data can be converted to the correct character set, thus avoiding garbled text issues. This article introduces several methods to resolve Chinese character encoding issues in Oracle databases.BackgroundOracle is recognized as a leading DBMS in the industry, ca...

GaDaddy is a famous web hosting platform where many people put their websites on its platform. If one has low budget and wanna a shared hosting, you can buy the service at GoDaddy and share some hosting resource with others. In such cases, there would be resource limit based on different plans.In this post, we will discuss one scenario which caused our application down caused by database usage on shared hosting plan and hope it helps readers who encounter similar issues.The issue we encountered is that our privileged users associated with the database we created get removed all of a sudden and...

In our daily work, there might be mistakes made which got some data or even databases deleted in MySQL. If this happens on production, it would be a nightmare. In case this happens, normally DBA would jump in to save the world. And they would try to recover the data from the backup if there is any. But if there is no backup, then the show stops.Hence database backup is necessary on production environments to avoid such awkward situation. Also normally in MySQL, binlog should be enabled as well in ROW mode so that recovery can be replayed starting from the backup time point to the incident time...

Nowadays, Redis has become one of the most popular cache solution in the Internet industry. Although relational database systems (SQL) bring many awesome properties such as ACID, the performance of the database would degrade under high load in order to maintain these properties.In order to fix this problem, many companies & websites have decided to add a cache layer between the application layer (i.e., the backend code which handles the business logic) and the storage layer (i.e., the SQL database). This cache layer is usually implemented using an in-memory cache. This is because, as state...

In a previous post, we discussed how the various relational operators are implemented in relational database systems. If you have read that post, you probably still remember that there are a few alternative implementations for every operator. Thus, how should RDBMS determine which algorithm (or implementation) to use?Obviously, to optimize the performance for any query, RDBMS has to select the correct the algorithm based on the query. It would not be desirable to always use the same algorithm. Also, SQL is a declarative language (i.e., as a programmer we only declare what we want to ...

We all know that DBMS (database management system) is used to store (a massive amount of) data. However, have you ever wondered how is data stored in DBMS? In this post, we will focus on data storage in RDBMS, the most traditional relational database systems.Physical StorageData can be stored in many different kinds of medium or devices, from the fastest but costy registers to the slow but cheap hard drives, or even magnetic tapes. Nowadays, IaaS providers such as AWS even provides services such as S3 Glacier as a low-cost archiving storage solution. The...

Oracle database is the most popular database system among enterprises. To start working on Oracle database, some concepts must be understood first. They include database, instance, schema and user etc. And among these concepts, some have different meanings from those in other database systems such as MS SQL, MySQL, DB2.On the web, there are already some good posts which explain different concepts such as Ask Tom's database vs instances, Difference between database vs user vs schema. In this post, these concepts with be summarized based on real application development experience.Database : A co...

The world of IT has to deal with the issue of data storage. The reason for this is that there is plenty of data produced and created daily on the internet and on various business applications. In the past, RDBMs or Relational Database Management Systems were used for storage. Even though they are still used today, there are other offerings that present competition and anyone wishing to purchase data storage systems needs to make comparisons. One such competing system is NoSQL or Not Only SQL. It has taken the market by storm because of the other possibilities that it offers which go beyon...