fluidb-old/DOC/RESTORE_FROM_SQLITE.md

# Restoring directly from SQLite

rqlite supports loading a node directly from two sources, either of which can be used to restore from an existing [node backup](https://github.com/rqlite/rqlite/blob/master/DOC/BACKUPS.md):
- An actual SQLite database file. This is the fastest way to initialize a rqlite node from an existing SQLite database.
- SQLite dump file. This is another convenient manner to initialize a system from an existing SQLite database. But if your source database is large, it can be slow.

## Examples
The following examples show a trivial database being generated by `sqlite3`, the SQLite file being backed up, converted to the corresponding list of SQL commands, and then loaded into a rqlite node listening on localhost using each form.

### HTTP
 _Be sure to set the Content-type header as shown, depending on the format of the upload._

```bash
~ $ sqlite3 restore.sqlite
SQLite version 3.14.1 2016-08-11 18:53:32
Enter ".help" for usage hints.
sqlite> CREATE TABLE foo (id integer not null primary key, name text);
sqlite> INSERT INTO "foo" VALUES(1,'fiona');
sqlite>
# Load directly from the SQLite file.
~ $ curl -v -XPOST localhost:4001/db/load -H "Content-type: application/octet-stream" --data-binary @restore.sqlite

# Convert SQLite database file to set of SQL commands and then load
~ $ echo '.dump' | sqlite3 restore.sqlite > restore.dump
~ $ curl -XPOST localhost:4001/db/load -H "Content-type: text/plain" --data-binary @restore.dump
```

After either command, we can connect to the node, and check that the data has been loaded correctly.
```bash
$ rqlite
127.0.0.1:4001> SELECT * FROM foo
+----+-------+
| id | name  |
+----+-------+
| 1  | fiona |
+----+-------+
```

### rqlite CLI
The CLI supports loading from a SQLite database file or dump file. Below shows an example of loading from the former.
```
~ $ sqlite3 restore.sqlite
SQLite version 3.22.0 2018-01-22 18:45:57
Enter ".help" for usage hints.
sqlite> CREATE TABLE foo (id integer not null primary key, name text);
sqlite> INSERT INTO "foo" VALUES(1,'fiona');
sqlite> 
~ $ ./rqlite 
Welcome to the rqlite CLI. Enter ".help" for usage hints.
127.0.0.1:4001> .schema
+-----+
| sql |
+-----+
127.0.0.1:4001> .restore restore.sqlite
database restored successfully
127.0.0.1:4001> select * from foo
+----+-------+
| id | name  |
+----+-------+
| 1  | fiona |
+----+-------+
```

## Caveats
The behavior of the restore operation when data already exists on the cluster is undefined -- you should only restore to a cluster that has no data, or a brand-new cluster. Also, please **note that SQLite dump files normally contain a command to disable Foreign Key constraints**. If you are running with Foreign Key Constraints enabled, and wish to re-enable this, this is the one time you should explicitly re-enable those constraints via the following `curl` command:
```bash
curl -XPOST 'localhost:4001/db/execute?pretty' -H "Content-Type: application/json" -d '[
    "PRAGMA foreign_keys = 1"
]'
```