> For the complete documentation index, see [llms.txt](https://docs.bdb.ai/7.6/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.bdb.ai/7.6/data-pipeline/components/readers/db-reader.md).

# DB Reader

The DB reader is a spark-based reader which gives you capability to read data from multiple database sources.

All component configurations are classified broadly into the following sections:

* [Basic ](/7.6/data-pipeline/components/component-base-configuration.md)
* Metadata
* [Resource Configuration](/7.6/data-pipeline/components/resource-configuration.md)
* [Connection Validation](/7.6/data-pipeline/components/connection-validation.md)

Please follow the demonstration to configure the component.

![RDBMS Writer](https://4128708524-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FGDmsjfjJBNqow7Fo97cO%2Fuploads%2FG6704jlNdYuDQlEaNXqk%2FRDBMS_reader.gif?alt=media\&token=7dd8bb97-4581-443d-b055-2161991f1855)

#### Drivers Available:

* MySQL
* Oracle
* PostgreSQL
* MS-SQL
* ClickHouse

{% hint style="warning" %}
Note: The ClickHouse driver in the Spark components will use HTTP Port and not the TCP port.
{% endhint %}

{% hint style="success" %}
In the case of data from multiple tables (join queries), one can write the join query directly without specifying multiple tables, as only one among table and query fields is required. 
{% endhint %}

Fetch Size: Provide the maximum number of records to be processed in one execution cycle.

Create Partition: This is used for performance enhancement. It's going to create the sequence of indexing.

      1\. Auto Increment: The number of partitions will be incremented automatically. 

     2\. Index: The number of partitions will be incremented based on the specified Partition column.

  Partition Column: specify a unique column name, whose value is a number .