Data nodes (DNs) in openGauss store data on disks. This section describes the objects on each DN from the logical view and the relationship between these objects. <a target="_blank" href="https://docs.opengauss.org/en/docs/latest/docs/Developerguide/database-logical-architecture.html#en-us_topic_0237120245_en-us_topic_0059779316_fb2fa3b3cc8824dea95318504e0537913">Figure 1</a> shows the database logical structure.
Figure 1 Database logical architecture
<img src="https://docs.opengauss.org/en/docs/latest/docs/Developerguide/figures/database-logical-architecture.png" alt />
<blockquote>
NOTE:
<ul>
<li>Tablespace: Directory storing physical files of its databases. Multiple tablespaces can coexist, and each of them can contain files belonging to different databases.
</li>
<li>Database: A database manages various data objects and is isolated from each other. Objects managed by a database can be distributed to multiple tablespaces.
</li>
<li>Datafile Segment: Data file, each of which stores data of only one table. A table containing more than 1 GB of data is stored in multiple datafile segments.
</li>
<li>One table belongs to only one database and one tablespace. The datafile segments storing the data of the same table must be in the same tablespace.
</li>
<li>Block: Basic unit of database management. Its default size is 8 KB.
</li>
</ul>
</blockquote>

Data nodes (DNs) in openGauss store data on disks. This section describes the objects on each DN from the logical view and the relationship between these objects. [Figure 1](https://docs.opengauss.org/en/docs/latest/docs/Developerguide/database-logical-architecture.html#en-us_topic_0237120245_en-us_topic_0059779316_fb2fa3b3cc8824dea95318504e0537913) shows the database logical structure.

**Figure 1** Database logical architecture

![](https://docs.opengauss.org/en/docs/latest/docs/Developerguide/figures/database-logical-architecture.png align="left")

> **NOTE:**
> 
> * Tablespace: Directory storing physical files of its databases. Multiple tablespaces can coexist, and each of them can contain files belonging to different databases.
>     
> * Database: A database manages various data objects and is isolated from each other. Objects managed by a database can be distributed to multiple tablespaces.
>     
> * Datafile Segment: Data file, each of which stores data of only one table. A table containing more than 1 GB of data is stored in multiple datafile segments.
>     
> * One table belongs to only one database and one tablespace. The datafile segments storing the data of the same table must be in the same tablespace.
>     
> * Block: Basic unit of database management. Its default size is 8 KB.
>

openGauss Database Logical Architecture