> For the complete documentation index, see [llms.txt](https://nag-9-s.gitbook.io/hbase/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://nag-9-s.gitbook.io/hbase/hbase-data-model.md).

# HBase Data Model

HBase Data model has four dimensions whereas RDBMS has two dimensional model ( row , columns)

![](https://1182370643-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LsbZSe32ZgrQ1gzZoPR%2F-LsbZZk03RhW1ap7TKI8%2F-LsbZ_BxRfh86uTBG7of%2Ffourdimesnsions.png?generation=1572621933894598\&alt=media)

* column families specified when the table is created and cannot be changed once the table is created.
* columns need not be declared when the table is created 
* column familiy can have any number of columns , dont need to specify upfront

![](https://1182370643-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LsbZSe32ZgrQ1gzZoPR%2F-LsbZZk03RhW1ap7TKI8%2F-LsbZ_Bz-ZEUG0Npo2d6%2Fdatamodel.png?generation=1572621934645521\&alt=media)

![](https://1182370643-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LsbZSe32ZgrQ1gzZoPR%2F-LsbZZk03RhW1ap7TKI8%2F-LsbZ_C2ZHhr6b0M7FDM%2FempDataModel.png?generation=1572621934281390\&alt=media)

![](https://1182370643-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LsbZSe32ZgrQ1gzZoPR%2F-LsbZZk03RhW1ap7TKI8%2F-LsbZ_CAtmdHJZUTnPxQ%2Fmodel.png?generation=1572621933334797\&alt=media)

![](https://1182370643-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LsbZSe32ZgrQ1gzZoPR%2F-LsbZZk03RhW1ap7TKI8%2F-LsbZ_CC35bqHe-K3IoG%2Fcolumnfamily.png?generation=1572621934028297\&alt=media)

![](https://1182370643-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LsbZSe32ZgrQ1gzZoPR%2F-LsbZZk03RhW1ap7TKI8%2F-LsbZ_CENIeMkrh6YvWb%2Fcolumn.png?generation=1572621934163705\&alt=media)