NoSQL databases are often categorised under four main types. Some databases are a mix between different types, but in general, they fit under the following main categories.
A column store database is a type of database that stores data using a column oriented model.
A column store database can also be referred to as a:
A document store database (also known as a document-oriented database, aggregate database, or simply document store or document database) is a database that uses a document-oriented model to store data.
Document store databases store each record and its associated data within a single document. Each document contains semi-structured data that can be queried against using various query and analytics tools of the DBMS.
A key-value database (also known as a key-value store and key-value store database) is a type of NoSQL database that uses a simple key/value method to store data.
The key-value part refers to the fact that the database stores data as a collection of key/value pairs. This is a simple method of storing data, and it is known to scale well.
NoSQL is a term that refers loosely to a particular type of database model, or database management system (DBMS).
NoSQL is a very broad term that doesn’t refer to one particular database model. Rather, it refers to a whole variety of different models that don’t fit into the relational model.
Although NoSQL databases have been around since the 1960s, it wasn’t until the early 2000s that the NoSQL approach started to pick up steam, and a whole new generation of NoSQL systems began to hit the market.
In database systems, ACID (Atomicity, Consistency, Isolation, Durability) refers to a standard set of properties that guarantee database transactions are processed reliably.
ACID is especially concerned with how a database recovers from any failure that might occur while processing a transaction.
An ACID-compliant DBMS ensures that the data in the database remains accurate and consistent despite any such failures.
This article lists the SQL
DROP TABLE syntax, as implemented by various database management systems (DBMSs). The syntax is listed exactly as each vendor has listed it on their website. Click on the applicable link to view more detail about the syntax for a particular vendor.
Oracle Database is often shortened to “Oracle” and sometimes “Oracle DB” or “Oracle RDBMS” (although it’s not the only product from Oracle Corporation).
Oracle Database runs on most major platforms, including Windows, UNIX, Linux and Mac OS.
PostgreSQL is an object-relational database management system (ORDBMS). It is an open source system that is known for its close alignment with the SQL standard.
This page contains 11 of the most commonly used SQL statements, along with a basic example of usage.
SQL is the standard language for querying relational databases. Each DBMS has varying levels of compliance with the SQL standard and so I’ve provided a link to a page that shows the specific syntax for each of the most popular RDBMSs.