copykatze 1b24d15c55
add advice to delete data via recorder services (#20445)
Co-authored-by: Franck Nijhof <frenck@frenck.nl>
2021-11-29 18:47:16 +01:00

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---
title: "Database"
description: "Details about the database used by Home Assistant."
---
Home Assistant uses database to store events and parameters for history and tracking. The default database used is [SQLite](https://www.sqlite.org/) and the database file is stored in your [configuration directory](/getting-started/configuration/) (e.g., `<path to config dir>/home-assistant_v2.db`); however, other databases can be used. If you prefer to run a database server (e.g., PostgreSQL), use the [`recorder` component](/integrations/recorder/).
To work with SQLite database manually from the command-line, you will need an [installation](https://www.sqlitetutorial.net/download-install-sqlite/) of `sqlite3`. Alternatively [DB Browser for SQLite](https://sqlitebrowser.org/) provides a viewer for exploring the database data and an editor for executing SQL commands.
First load your database with `sqlite3`:
```bash
$ sqlite3 home-assistant_v2.db
SQLite version 3.13.0 2016-05-18 10:57:30
Enter ".help" for usage hints.
sqlite>
```
It helps to set some options to make the output more readable:
```bash
sqlite> .header on
sqlite> .mode column
```
You could also start `sqlite3` and attach the database later. Not sure what database you are working with? Check it, especially if you are going to delete data.
```bash
sqlite> .databases
seq name file
--- --------------- ----------------------------------------------------------
0 main /home/fab/.homeassistant/home-assistant_v2.db
```
### Schema
Get all available tables from your current Home Assistant database:
```bash
sqlite> SELECT sql FROM sqlite_master;
-------------------------------------------------------------------------------------
CREATE TABLE events (
event_id INTEGER NOT NULL,
event_type VARCHAR(32),
event_data TEXT,
origin VARCHAR(32),
time_fired DATETIME,
created DATETIME,
context_id VARCHAR(36),
context_user_id VARCHAR(36), context_parent_id CHARACTER(36),
PRIMARY KEY (event_id)
)
CREATE TABLE recorder_runs (
run_id INTEGER NOT NULL,
start DATETIME,
"end" DATETIME,
closed_incorrect BOOLEAN,
created DATETIME,
PRIMARY KEY (run_id),
CHECK (closed_incorrect IN (0, 1))
)
CREATE TABLE schema_changes (
change_id INTEGER NOT NULL,
schema_version INTEGER,
changed DATETIME,
PRIMARY KEY (change_id)
)
CREATE TABLE states (
state_id INTEGER NOT NULL,
domain VARCHAR(64),
entity_id VARCHAR(255),
state VARCHAR(255),
attributes TEXT,
event_id INTEGER,
last_changed DATETIME,
last_updated DATETIME,
created DATETIME,
context_id VARCHAR(36),
context_user_id VARCHAR(36), context_parent_id CHARACTER(36), old_state_id INTEGER,
PRIMARY KEY (state_id),
FOREIGN KEY(event_id) REFERENCES events (event_id)
)
CREATE TABLE sqlite_stat1(tbl,idx,stat)
CREATE INDEX ix_events_context_user_id ON events (context_user_id)
CREATE INDEX ix_events_event_type ON events (event_type)
CREATE INDEX ix_events_context_id ON events (context_id)
CREATE INDEX ix_events_time_fired ON events (time_fired)
CREATE INDEX ix_recorder_runs_start_end ON recorder_runs (start, "end")
CREATE INDEX ix_states_entity_id ON states (entity_id)
CREATE INDEX ix_states_context_user_id ON states (context_user_id)
CREATE INDEX ix_states_last_updated ON states (last_updated)
CREATE INDEX ix_states_event_id ON states (event_id)
CREATE INDEX ix_states_entity_id_last_updated ON states (entity_id, last_updated)
CREATE INDEX ix_states_context_id ON states (context_id)
CREATE INDEX ix_states_context_parent_id ON states (context_parent_id)
CREATE INDEX ix_events_context_parent_id ON events (context_parent_id)
```
To only show the details about the `states` table (since we are using that one in the next examples):
```bash
sqlite> SELECT sql FROM sqlite_master WHERE type = 'table' AND tbl_name = 'states';
```
### Query
The identification of the available columns in the table is done and we are now able to create a query. Let's list your Top 10 entities:
```bash
sqlite> .width 30, 10,
sqlite> SELECT entity_id, COUNT(*) as count FROM states GROUP BY entity_id ORDER BY count DESC LIMIT 10;
entity_id count
------------------------------ ----------
sensor.cpu 28874
sun.sun 21238
sensor.time 18415
sensor.new_york 18393
cover.kitchen_cover 17811
switch.mystrom_switch 14101
sensor.internet_time 12963
sensor.solar_angle1 11397
sensor.solar_angle 10440
group.all_switches 8018
```
### Delete
If you don't want to keep certain entities, you can delete them permanently by using the [services provided by the recorder](/integrations/recorder/#service-purge_entities).
For a more interactive way of working with the database, check the [Data Science Portal](https://data.home-assistant.io/).