What is the difference between a database and a data warehouse?
Aren't they the same thing, or at least written in the same thing (ie. Oracle RDBMS)?
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database
data-warehouse
DataBase :- OLTP(online transaction process)
Datawarehouse
From a Non-Technical View: A database is constrained to a particular applications or set of applications.
A data warehouse is an enterprise level data repository. It's going to contain data from all/many segments of the business. It's going to share this information to provide a global picture of the business. It is also critical to integration between the different segments of the business.
From a Technical view: The word "Data Warehouse" has been given no recognized definition. Personally, I define a data warehouse as a collection of data-marts. Where each data-mart consists of one or more databases where the database is specific to a specific problem set (application, data-set or process).
Simply put a database is a component of a data-warehouse. There are many places to explore this concept, but because there is no "definition", you will find challenges with any answer you give.
A data warehouse is a TYPE of database.
In addition to what folks have already said, data warehouses tend to be OLAP, with indexes, etc. tuned for reading, not writing, and the data is de-normalized / transformed into forms that are easier to read & analyze.
Some folks have said "databases" are the same as OLTP -- this isn't true. OLTP, again, is a TYPE of database.
Other types of "databases": Text files, XML, Excel, CSV..., Flat Files :-)
A Data Warehouse is a type of Data Structure usually housed on a Database. The Data Warehouse refers the the data model and what type of data is stored there - data that is modeled (data model) to server an analytical purpose.
A Database can be classified as any structure that houses data. Traditionally that would be an RDBMS like Oracle, SQL Server, or MySQL. However a Database can also be a NoSQL Database like Apache Cassandra, or an columnar MPP like AWS RedShift.
You see a database is simply a place to store data; a data warehouse is a specific way to store data and serves a specific purpose, which is to serve analytical queries.
OLTP vs OLAP does not tell you the difference between a DW and a Database, both OLTP and OLAP reside on databases. They just store data in a different fashion (different data model methodologies) and serve different purposes (OLTP - record transactions, optimized for updates; OLAP - analyze information, optimized for reads).
Any data storage for application generally uses the database. It could be relational database or no sql databases which are currently trending.
Data warehouse is also database. We can call data warehouse database as specialized data storage for the analytical reporting purposes for the company. This data used for key business decision.
The organized data helps is reporting and taking business decision effectively.
Example: A house is worth $100,000, and it is appreciating at $1000 per year.
To keep track of the current house value, you would use a database as the value would change every year.
Three years later, you would be able to see the value of the house which is $103,000.
To keep track of the historical house value, you would use a data warehouse as the value of the house should be
$100,000 on year 0,
$101,000 on year 1,
$102,000 on year 2,
$103,000 on year 3.
The simplest way to explain it would be to say that a data warehouse consists of more than just a database. A database is an collection of data organized in some way, but a data warehouse is organized specifically to "facilitate reporting and analysis". This however is not the entire story as data warehousing also contains "the means to retrieve and analyze data, to extract, transform and load data, and to manage the data dictionary are also considered essential components of a data warehousing system".
A Data Warehousing (DW) is process for collecting and managing data from varied sources to provide meaningful business insights. A Data warehouse is typically used to connect and analyze business data from heterogeneous sources. The data warehouse is the core of the BI system which is built for data analysis and reporting.
Source for the Data warehouse can be cluster of Databases, because databases are used for Online Transaction process like keeping the current records..but in Data warehouse it stores historical data which are for Online analytical process.
See in simple words : Dataware --> Huge data using for Analytical/storage/ copy and Analysis . Database --> CRUD operation with Frequently used data .
Dataware house is Kind of storage which u are not using on daily basis & Database is something which your dealing frequently .
Eg. If we are asking statement of bank then it gives us for last 3/4/6/more months bcoz it is in database. If you want more than that it stores on Dataware house.
Data Warehouse vs Database: A data warehouse is specially designed for data analytics, which involves reading large amounts of data to understand relationships and trends across the data. A database is used to capture and store data, such as recording details of a transaction.
Data Warehouse: Suitable workloads - Analytics, reporting, big data. Data source - Data collected and normalized from many sources. Data capture - Bulk write operations typically on a predetermined batch schedule. Data normalization - Denormalized schemas, such as the Star schema or Snowflake schema. Data storage - Optimized for simplicity of access and high-speed query. performance using columnar storage. Data access - Optimized to minimize I/O and maximize data throughput.
Transactional Database: Suitable workloads - Transaction processing. Data source - Data captured as-is from a single source, such as a transactional system. Data capture - Optimized for continuous write operations as new data is available to maximize transaction throughput. Data normalization - Highly normalized, static schemas. Data storage - Optimized for high throughout write operations to a single row-oriented physical block. Data access - High volumes of small read operations.
Database:
Used for Online Transactional Processing (OLTP).
Data Warehouse:
Used for Online Analytical Processing (OLAP).
Check out this for more information.
From a previous link:
Database
Data Warehouse
It's important to note as well that Data Warehouses could be sourced from zero to many databases.
Source: Stackoverflow.com