| --- | |
| title: "Tool Layer Schema" | |
| description: > | |
| Extract raw data into a relational schema for each specific tool | |
| sidebar_position: 2 | |
| --- | |
| ## Summary | |
| This document describes Apache DevLake's tool layer schema. | |
| Referring to DevLake's [architecture](../Overview/Architecture.md), the Tool layer extracts raw data from JSONs into a relational schema that's easier to consume by analytical tasks. Each DevOps tool would have a schema that's tailored to its data structure, hence the name, the Tool layer. | |
| ## Use Cases | |
| As a user, you can check tool data tables to verify data quality if you have concerns about the [domain layer data](DevLakeDomainLayerSchema.md). | |
| ## Data Models | |
| Tool layer tables start with a prefix `_tool_`. Each plugin contains multiple tool data tables, the naming convension of these tables is `_raw_{plugin}_{entity}`. For instance, | |
| - _tool_jira_issues | |
| - _tool_jira_boards | |
| - _tool_jira_board_issues` | |
| - ... | |
| Normally, you do not need to use tool layer tables, unless you have one of the above use cases. |