Documentation enhancements (#73)

docs/stores/sql.md

@@ -0,0 +1,98 @@
+# SQL Identity store
+## Supported Databases
+- PostgreSQL
+- MariaDB
+- MySQL
+- SQLite
+
+## Features
+|      Name      | Supported? |
+|----------------|------------|
+| Authentication | No         |
+| Directory      | Yes        |
+| Identity       | Yes        |
+
+Due to the implementation complexity of supporting arbitrary hashing/encoding mechanisms or auth flow, Authentication
+will be out of scope of SQL Identity stores and should be done via one of the other identity stores, typically
+the [REST Identity store](rest.md).
+
+## Configuration
+### Basic
+```yaml
+sql.enabled: <boolean>
+```
+Enable/disable the identity store
+
+---
+
+```yaml
+sql.type: <string>
+```
+Set the SQL backend to use:
+- `sqlite`
+- `postgresql`
+- `mariadb`
+- `mysql`
+
+### Connection
+#### SQLite
+```yaml
+sql.connection: <string>
+```
+Set the value to the absolute path to the Synapse SQLite DB file.
+Example: `/path/to/sqlite/file.db`
+
+#### Others
+```yaml
+sql.connection: //<HOST[:PORT]/DB?username=USER&password=PASS
+```
+Set the connection info for the database by replacing the following values:
+- `HOST`: Hostname of the SQL server
+- `PORT`: Optional port value, if not default
+- `DB`: Database name
+- `USER`: Username for the connection
+- `PASS`: Password for the connection
+
+This follow the JDBC URI syntax. See [official website](https://docs.oracle.com/javase/tutorial/jdbc/basics/connecting.html#db_connection_url).
+
+### Directory
+```yaml
+sql.directory.enabled: false
+```
+
+
+---
+
+```yaml
+sql.directory.query:
+  name:
+    type: <string>
+    value: <string>
+  threepid:
+    type: <string>
+    value: <string>
+```
+For each query, `type` can be used to tell mxisd how to process the ID column:
+- `localpart` will append the `matrix.domain` to it
+- `mxid` will use the ID as-is. If it is not a valid Matrix ID, the search will fail.
+
+`value` is the SQL query and must return two columns:
+- The first being the User ID
+- The second being its display name
+
+Example:
+```yaml
+sql.directory.query:
+  name:
+    type: 'localpart'
+    value: 'SELECT idColumn, displayNameColumn FROM table WHERE displayNameColumn LIKE ?'
+  threepid:
+    type: 'localpart'
+    value: 'SELECT idColumn, displayNameColumn FROM table WHERE threepidColumn LIKE ?'
+```
+
+### Identity
+```yaml
+sql.identity.type: <string>
+sql.identity.query: <string>
+```