@@ -2,55 +2,56 @@
22
33[](https://github.com/fabianlindfors/reshape/actions/workflows/test.yaml) [](https://github.com/fabianlindfors/reshape/releases)
44
5+> Also check out [ReshapeDB](https://reshapedb.com), a new database built from the ground up to make zero-downtime schema and data migrations as simple and safe as possible. If you'd like to chat about it, please [reach out](contact@reshapedb.com)!
6+
57Reshape is an easy-to-use, zero-downtime schema migration tool for Postgres. It automatically handles complex migrations that would normally require downtime or manual multi-step changes. During a migration, Reshape ensures both the old and new schema are available at the same time, allowing you to gradually roll out your application. It will also perform all changes without excessive locking, avoiding downtime caused by blocking other queries. For a more thorough introduction to Reshape, check out the [introductory blog post](https://fabianlindfors.se/blog/schema-migrations-in-postgres-using-reshape/).
68
79Designed for Postgres 12 and later.
810
9−*Note: Reshape is **experimental** and should not be used in production. It can (and probably will) break your application.*
10−
1111- [How it works](#how-it-works)
1212- [Getting started](#getting-started)
13− - [Installation](#installation)
14− - [Creating your first migration](#creating-your-first-migration)
15− - [Preparing your application](#preparing-your-application)
16− - [Running your migration](#running-your-migration)
17− - [Using during development](#using-during-development)
13+ - [Installation](#installation)
14+ - [Creating your first migration](#creating-your-first-migration)
15+ - [Preparing your application](#preparing-your-application)
16+ - [Running your migration](#running-your-migration)
17+ - [Using during development](#using-during-development)
1818- [Writing migrations](#writing-migrations)
19− - [Basics](#basics)
20− - [Tables](#tables)
21− - [Create table](#create-table)
22− - [Rename table](#rename-table)
23− - [Remove table](#remove-table)
24− - [Add foreign key](#add-foreign-key)
25− - [Remove foreign key](#remove-foreign-key)
26− - [Columns](#columns)
27− - [Add column](#add-column)
28− - [Alter column](#alter-column)
29− - [Remove column](#remove-column)
30− - [Indices](#indices)
31− - [Add index](#add-index)
32− - [Remove index](#remove-index)
33− - [Enums](#enums)
34− - [Create enum](#create-enum)
35− - [Remove enum](#remove-enum)
19+ - [Basics](#basics)
20+ - [Tables](#tables)
21+ - [Create table](#create-table)
22+ - [Rename table](#rename-table)
23+ - [Remove table](#remove-table)
24+ - [Add foreign key](#add-foreign-key)
25+ - [Remove foreign key](#remove-foreign-key)
26+ - [Columns](#columns)
27+ - [Add column](#add-column)
28+ - [Alter column](#alter-column)
29+ - [Remove column](#remove-column)
30+ - [Indices](#indices)
31+ - [Add index](#add-index)
32+ - [Remove index](#remove-index)
33+ - [Enums](#enums)
34+ - [Create enum](#create-enum)
35+ - [Remove enum](#remove-enum)
36+ - [Custom](#custom)
37+ - [Complex changes across tables](#complex-changes-across-tables)
3638- [Commands and options](#commands-and-options)
37− - [`reshape migrate`](#reshape-migrate)
38− - [`reshape complete`](#reshape-complete)
39− - [`reshape abort`](#reshape-abort)
40− - [`reshape generate-schema-query`](#reshape-generate-schema-query)
41− - [Connection options](#connection-options)
39+ - [`reshape migration start`](#reshape-migration-start)
40+ - [`reshape migration complete`](#reshape-migration-complete)
41+ - [`reshape migration abort`](#reshape-migration-abort)
42+ - [`reshape schema-query`](#reshape-schema-query)
43+ - [Connection options](#connection-options)
4244- [License](#license)
4345
44−
4546## How it works
4647
4748Reshape works by creating views that encapsulate the underlying tables, which your application will interact with. During a migration, Reshape will automatically create a new set of views and set up triggers to translate inserts and updates between the old and new schema. This means that every deployment is a three-phase process:
4849
49−1. **Start migration** (`reshape migrate`): Sets up views and triggers to ensure both the new and old schema are usable at the same time.
50+1. **Start migration** (`reshape migration start`): Sets up views and triggers to ensure both the new and old schema are usable at the same time.
50512. **Roll out application**: Your application can be gradually rolled out without downtime. The existing deployment will continue using the old schema whilst the new deployment uses the new schema.
51−3. **Complete migration** (`reshape complete`): Removes the old schema and any intermediate data and triggers.
52+3. **Complete migration** (`reshape migration complete`): Removes the old schema and any intermediate data and triggers.
5253
53−If the application deployment fails, you should run `reshape abort` which will roll back any changes made by `reshape migrate` without losing data.
54+If the application deployment fails, you should run `reshape migration abort` which will roll back any changes made by `reshape migration start` without losing data.
5455
5556## Getting started
5657
@@ -70,10 +71,10 @@ cargo install reshape
7071
7172#### Docker
7273
73−Reshape is available as a Docker image on [Docker Hub](https://hub.docker.com/repository/docker/fabianlindfors/reshape).
74+Reshape is available as a Docker image on [Docker Hub](https://hub.docker.com/repository/docker/fabianlindfors/reshape).
7475
7576```shell
76−docker run -v $(pwd):/usr/share/app fabianlindfors/reshape reshape migrate
77+docker run -v $(pwd):/usr/share/app fabianlindfors/reshape reshape migration start
7778```
7879
7980### Creating your first migration
@@ -102,9 +103,14 @@ This is the equivalent of running `CREATE TABLE users (id INTEGER GENERATED ALWA
102103
103104### Preparing your application
104105
105−Reshape relies on your application using a specific schema. When establishing the connection to Postgres in your application, you need to run a query to select the most recent schema. This query can be generated using: `reshape generate-schema-query`.
106+Reshape relies on your application using a specific schema. When establishing the connection to Postgres in your application, you need to run a query to select the most recent schema. The simplest way to do this is to use one of the helper libraries:
107+
108+- [Rust](https://github.com/fabianlindfors/reshape-helper)
109+- [Ruby (and Rails)](https://github.com/fabianlindfors/reshape-ruby)
110+- [Python (and Django)](https://github.com/fabianlindfors/reshape-python)
111+- [Go](https://github.com/leourbina/reshape-helper)
106112
107−To pass it along to your application, you can for example use an environment variable in your run script: `RESHAPE_SCHEMA_QUERY=$(reshape generate-schema-query)`. Then in your application:
113+If your application is not using one of the languages with an available helper library, you can instead generate the query with the command: `reshape schema-query`. To pass it along to your application, you can for example use an environment variable in your run script: `RESHAPE_SCHEMA_QUERY=$(reshape schema-query)`. Then in your application:
108114
109115```python
110116# Example for Python
@@ -112,23 +118,21 @@ reshape_schema_query = os.getenv("RESHAPE_SCHEMA_QUERY")
112118db.execute(reshape_schema_query)
113119```
114120
115−If your application is written in Rust, you might prefer the [Rust helper library](https://github.com/fabianlindfors/reshape-helper) which embeds the query directly in your application with a macro.
116−
117121### Running your migration
118122
119123To create your new `users` table, run:
120124
121125```bash
122−reshape migrate --complete
126+reshape migration start --complete
123127```
124128
125−We use the `--complete` flag to automatically complete the migration. During a production deployment, you should first run `reshape migrate` followed by `reshape complete` once your application has been fully rolled out.
129+We use the `--complete` flag to automatically complete the migration. During a production deployment, you should first run `reshape migration start` followed by `reshape migration complete` once your application has been fully rolled out.
126130
127131If nothing else is specified, Reshape will try to connect to a Postgres database running on `localhost` using `postgres` as both username and password. See [Connection options](#connection-options) for details on how to change the connection settings.
128132
129133### Using during development
130134
131−When adding new migrations during development, we recommend running `reshape migrate` but skipping `reshape complete`. This way, the new migrations can be iterated on by updating the migration file and running `reshape abort` followed by `reshape migrate`.
135+When adding new migrations during development, we recommend running `reshape migration start` but skipping `reshape migration complete`. This way, the new migrations can be iterated on by updating the migration file and running `reshape migration abort` followed by `reshape migration start`.
132136
133137## Writing migrations
134138
@@ -163,9 +167,9 @@ Every action has a `type`. The supported types are detailed below.
163167
164168#### Create table
165169
166−The `create_table` action will create a new table with the specified columns, indices and constraints.
170+The `create_table` action will create a new table with the specified columns, indices and constraints. You can optionally provide an `up` option to backfill values from an existing table.
167171
168−*Example: create a `customers` table with a few columns and a primary key*
172+_Example: create a `customers` table with a few columns and a primary key_
169173
170174```toml
171175[[actions]]
@@ -183,13 +187,13 @@ primary_key = ["id"]
183187 type = "TEXT"
184188
185189 # Columns default to nullable
186− nullable = false
190+ nullable = false
187191
188192 # default can be any valid SQL value, in this case a string literal
189− default = "'PLACEHOLDER'"
193+ default = "'PLACEHOLDER'"
190194```
191195
192−*Example: create `users` and `items` tables with a foreign key between them*
196+_Example: create `users` and `items` tables with a foreign key between them_
193197
194198```toml
195199[[actions]]
@@ -222,11 +226,34 @@ primary_key = ["id"]
222226 referenced_columns = ["id"]
223227```
224228
229+_Example: create `profiles` table based on existing `users` table_
230+
231+```toml
232+[[actions]]
233+type = "create_table"
234+name = "profiles"
235+primary_key = ["user_id"]
236+
237+ [[actions.columns]]
238+ name = "user_id"
239+ type = "INTEGER"
240+
241+ [[actions.columns]]
242+ name = "user_email"
243+ type = "TEXT"
244+
245+ # Backfill from `users` table and copy `users.email` to `user_email` column
246+ # This will perform an upsert based on the primary key to avoid duplicate rows
247+ [actions.up]
248+ table = "users"
249+ values = { user_id = "id", user_email = "email" }
250+```
251+
225252#### Rename table
226253
227254The `rename_table` action will change the name of an existing table.
228255
229−*Example: change name of `users` table to `customers`*
256+_Example: change name of `users` table to `customers`_
230257
231258```toml
232259[[actions]]
@@ -239,7 +266,7 @@ new_name = "customers"
239266
240267The `remove_table` action will remove an existing table.
241268
242−*Example: remove `users` table*
269+_Example: remove `users` table_
243270
244271```toml
245272[[actions]]
@@ -251,7 +278,7 @@ table = "users"
251278
252279The `add_foreign_key` action will add a foreign key between two existing tables. The migration will fail if the existing column values aren't valid references.
253280
254−*Example: create foreign key from `items` to `users` table*
281+_Example: create foreign key from `items` to `users` table_
255282
256283```toml
257284[[actions]]
@@ -268,7 +295,7 @@ table = "items"
268295
269296The `remove_foreign_key` action will remove an existing foreign key. The foreign key will only be removed once the migration is completed, which means that your new application must continue to adhere to the foreign key constraint.
270297
271−*Example: remove foreign key `items_user_id_fkey` from `users` table*
298+_Example: remove foreign key `items_user_id_fkey` from `users` table_
272299
273300```toml
274301[[actions]]
@@ -281,9 +308,9 @@ foreign_key = "items_user_id_fkey"
281308
282309#### Add column
283310
284−The `add_column` action will add a new column to an existing table. You can optionally provide an `up` setting. This should be an SQL expression which will be run for all existing rows to backfill the new column.
311+The `add_column` action will add a new column to an existing table. You can optionally provide an `up` setting. This should be an SQL expression which will be run for all existing rows to backfill the new column. `up` may also reference another table to perform cross-table migrations (see ["Complex changes across tables"](#complex-changes-across-tables)).
285312
286−*Example: add a new column `reference` to table `products`*
313+_Example: add a new column `reference` to table `products`_
287314
288315```toml
289316[[actions]]
@@ -297,7 +324,7 @@ table = "products"
297324 default = "10"
298325```
299326
300−*Example: replace an existing `name` column with two new columns, `first_name` and `last_name`*
327+_Example: replace an existing `name` column with two new columns, `first_name` and `last_name`_
301328
302329```toml
303330[[actions]]
@@ -333,7 +360,7 @@ column = "name"
333360down = "first_name || ' ' || last_name"
334361```
335362
336−*Example: extract nested value from unstructured JSON `data` column to new `name` column*
363+_Example: extract nested value from unstructured JSON `data` column to new `name` column_
337364
338365```toml
339366[[actions]]
@@ -348,6 +375,25 @@ up = "data['path']['to']['value'] #>> '{}'"
348375 type = "TEXT"
349376```
350377
378+_Example: duplicate `email` column from `users` to `profiles` table_
379+
380+```toml
381+# `profiles` has `user_id` column which maps to `users.id`
382+[[actions]]
383+type = "add_column"
384+table = "profiles"
385+
386+ [actions.column]
387+ name = "email"
388+ type = "TEXT"
389+ nullable = false
390+
391+ # When `users` is updated in the old schema, we write the email value to `profiles`
392+ [actions.up]
393+ table = "users"
394+ value = "email"
395+ where = "user_id = id"
396+```
351397
352398#### Alter column
353399
@@ -355,7 +401,7 @@ The `alter_column` action enables many different changes to an existing column,
355401
356402When performing more complex changes than a rename, `up` and `down` should be provided. These should be SQL expressions which determine how to transform between the new and old version of the column. Inside those expressions, you can reference the current column value by the column name.
357403
358−*Example: rename `last_name` column on `users` table to `family_name`*
404+_Example: rename `last_name` column on `users` table to `family_name`_
359405
360406```toml
361407[[actions]]
@@ -367,7 +413,7 @@ column = "last_name"
367413 name = "family_name"
368414```
369415
370−*Example: change the type of `reference` column from `INTEGER` to `TEXT`*
416+_Example: change the type of `reference` column from `INTEGER` to `TEXT`_
371417
372418```toml
373419[[actions]]
@@ -382,7 +428,7 @@ down = "CAST(reference AS INTEGER)" # Converts from text value to integer
382428 type = "TEXT" # Previous type was 'INTEGER'
383429```
384430
385−*Example: increment all values of an `index` column by one*
431+_Example: increment all values of an `index` column by one_
386432
387433```toml
388434[[actions]]
@@ -397,7 +443,7 @@ down = "index - 1" # Decrement to revert for old schema
397443 name = "index"
398444```
399445
400−*Example: make `name` column not nullable*
446+_Example: make `name` column not nullable_
401447
402448```toml
403449[[actions]]
@@ -412,7 +458,7 @@ up = "COALESCE(name, 'N/A')"
412458 nullable = false
413459```
414460
415−*Example: change default value of `created_at` column to current time*
461+_Example: change default value of `created_at` column to current time_
416462
417463```toml
418464[[actions]]
@@ -426,11 +472,11 @@ column = "created_at"
426472
427473#### Remove column
428474
429−The `remove_column` action will remove an existing column from a table. You can optionally provide a `down` setting. This should be an SQL expression which will be used to determine values for the old schema when inserting or updating rows using the new schema. The `down` setting must be provided when the removed column is `NOT NULL` or doesn't have a default value.
475+The `remove_column` action will remove an existing column from a table. You can optionally provide a `down` setting. This should be an SQL expression which will be used to determine values for the old schema when inserting or updating rows using the new schema. `down` may also reference another table to perform cross-table migrations (see ["Complex changes across tables"](#complex-changes-across-tables)) . The `down` setting must be provided when the removed column is `NOT NULL` or doesn't have a default value.
430476
431477Any indices that cover the column will be removed.
432478
433−*Example: remove column `name` from table `users`*
479+_Example: remove column `name` from table `users`_
434480
435481```toml
436482[[actions]]
@@ -442,18 +488,34 @@ column = "name"
442488down = "'N/A'"
443489```
444490
491+_Example: remove `email` column from `users` table and use column from `profiles` table instead_
492+
493+```toml
494+[[actions]]
495+type = "remove_column"
496+table = "users"
497+column = "email"
498+
499+ # Our application will use the `profiles.email` column instead
500+ # For backwards compatibility, we will write back to the removed `email` column whenever `profiles` is changed
501+ [actions.down]
502+ table = "profiles"
503+ value = "profiles.email"
504+ where = "users.id = profiles.user_id"
505+```
506+
445507### Indices
446508
447509#### Add index
448510
449511The `add_index` action will add a new index to an existing table.
450512
451−*Example: create a `users` table with a unique index on the `name` column*
513+_Example: create a `users` table with a unique index on the `name` column_
452514
453515```toml
454516[[actions]]
455517type = "create_table"
456−table = "users"
518+name = "users"
457519primary_key = "id"
458520
459521 [[actions.columns]]
@@ -477,7 +539,7 @@ table = "users"
477539 unique = true
478540```
479541
480−*Example: add GIN index to `data` column on `products` table*
542+_Example: add GIN index to `data` column on `products` table_
481543
482544```toml
483545[[actions]]
@@ -496,7 +558,7 @@ table = "products"
496558
497559The `remove_index` action will remove an existing index. The index won't actually be removed until the migration is completed.
498560
499−*Example: remove the `name_idx` index*
561+_Example: remove the `name_idx` index_
500562
501563```toml
502564[[actions]]
@@ -510,7 +572,7 @@ index = "name_idx"
510572
511573The `create_enum` action will create a new [enum type](https://www.postgresql.org/docs/current/datatype-enum.html) with the specified values.
512574
513−*Example: add a new `mood` enum type with three possible values*
575+_Example: add a new `mood` enum type with three possible values_
514576
515577```toml
516578[[actions]]
@@ -523,7 +585,7 @@ values = ["happy", "ok", "sad"]
523585
524586The `remove_enum` action will remove an existing [enum type](https://www.postgresql.org/docs/current/datatype-enum.html). Make sure all usages of the enum has been removed before running the migration. The enum will only be removed once the migration is completed.
525587
526−*Example: remove the `mood` enum type*
588+_Example: remove the `mood` enum type_
527589
528590```toml
529591[[actions]]
@@ -531,47 +593,162 @@ type = "remove_enum"
531593enum = "mood"
532594```
533595
596+### Custom
597+
598+The `custom` action lets you create a migration which runs custom SQL. It should be used with great care as it provides no guarantees of zero-downtime and will simply run whatever SQL is provided. Use other actions whenever possible as they are explicitly designed for zero downtime.
599+
600+There are three optional settings available which all accept SQL queries. All queries need to be idempotent, for example by using `IF NOT EXISTS` wherever available.
601+
602+- `start`: run when a migration is started using `reshape migration start`
603+- `complete`: run when a migration is completed using `reshape migration complete`
604+- `abort`: run when a migration is aborted using `reshape migration abort`
605+
606+_Example: enable PostGIS and pg_stat_statements extensions_
607+
608+```toml
609+[[actions]]
610+type = "custom"
611+
612+start = """
613+ CREATE EXTENSION IF NOT EXISTS postgis;
614+ CREATE EXTENSION IF NOT EXISTS pg_stat_statements;
615+"""
616+
617+abort = """
618+ DROP EXTENSION IF EXISTS postgis;
619+ DROP EXTENSION IF EXISTS pg_stat_statements;
620+"""
621+```
622+
623+### Complex changes across tables
624+
625+The `up` and `down` options available when creating tables, adding columns and removing columns can also perform more complex changes that span tables.
626+
627+_Example: move `email` column from `users` to `profiles` table_
628+
629+```toml
630+[[actions]]
631+type = "add_column"
632+table = "profiles"
633+
634+ [actions.column]
635+ name = "email"
636+ type = "TEXT"
637+ nullable = false
638+
639+ # When `users` is updated in the old schema, we write the email value to `profiles`
640+ [actions.up]
641+ table = "users"
642+ value = "users.email"
643+ where = "profiles.user_id = users.id"
644+
645+[[actions]]
646+type = "remove_column"
647+table = "users"
648+column = "email"
649+
650+ # When `profiles` is changed in the new schema, we write the email address back to the removed column
651+ [actions.down]
652+ table = "profiles"
653+ value = "profiles.email"
654+ where = "users.id = profiles.user_id"
655+```
656+
657+_Example: turn a 1:N relationship between `users` and `accounts` into N:M and change the format of the associated `role`_
658+
659+```toml
660+# Add `user_account_connections` as a junction table
661+[[actions]]
662+type = "create_table"
663+name = "user_account_connections"
664+primary_key = ["account_id", "user_id"]
665+
666+ [[actions.columns]]
667+ name = "account_id"
668+ type = "INTEGER"
669+
670+ [[actions.columns]]
671+ name = "user_id"
672+ type = "INTEGER"
673+
674+ # `role` is currently stored directly on the `users` table but is part of the relationship
675+ [[actions.columns]]
676+ name = "role"
677+ type = "TEXT"
678+ nullable = false
679+
680+ # Backfill the new table from `users` and uppercase the `role`
681+ [actions.up]
682+ table = "users"
683+ values = { user_id = "id", account_id = "account_id", role = "UPPER(account_role)" }
684+ where = "user_account_connections.user_id = users.id"
685+
686+[[actions]]
687+type = "remove_column"
688+table = "users"
689+column = "account_id"
690+
691+ # When `user_account_connections` is updated, we write the `account_id` back to `users`
692+ [actions.down]
693+ table = "user_account_connections"
694+ value = "user_account_connections.account_id"
695+ where = "users.id = user_account_connections.user_id"
696+
697+[[actions]]
698+type = "remove_column"
699+table = "users"
700+column = "account_role"
701+
702+ # When `user_account_connections` is updated, we write the lowercase role back to `users`
703+ [actions.down]
704+ table = "user_account_connections"
705+ value = "LOWER(user_account_connections.role)"
706+ where = "users.id = user_account_connections.user_id"
707+```
708+
534709## Commands and options
535710
536−### `reshape migrate`
711+### `reshape migration start`
537712
538−Starts a new migration, applying all migrations under `migrations/` that haven't yet been applied. After the command has completed, both the old and new schema will be usable at the same time. When you have rolled out the new version of your application which uses the new schema, you should run `reshape complete`.
713+Starts a new migration, applying all migrations under `migrations/` that haven't yet been applied. After the command has completed, both the old and new schema will be usable at the same time. When you have rolled out the new version of your application which uses the new schema, you should run `reshape migration complete`.
539714
540715#### Options
541716
542−*See also [Connection options](#connection-options)*
717+_See also [Connection options](#connection-options)_
543718
544−| Option | Default | Description |
545−| ------ | ------- | ----------- |
546−| `--complete`, `-c` | `false` | Automatically complete migration after applying it. |
547−| `--dirs` | `migrations/` | Directories to search for migration files. Multiple directories can be specified using `--dirs dir1 dir2 dir3`. |
719+| Option | Default | Description |
720+| ------------------ | ------------- | --------------------------------------------------------------------------------------------------------------- |
721+| `--complete`, `-c` | `false` | Automatically complete migration after applying it. |
722+| `--dirs` | `migrations/` | Directories to search for migration files. Multiple directories can be specified using `--dirs dir1 dir2 dir3`. |
548723
549−### `reshape complete`
724+### `reshape migration complete`
550725
551−Completes migrations previously started with `reshape complete`.
726+Completes migrations previously started with `reshape migration complete`.
552727
553728#### Options
554729
555730See [Connection options](#connection-options)
556731
557−### `reshape abort`
732+### `reshape migration abort`
558733
559−Aborts any migrations which haven't yet been completed.
734+Aborts any migrations which haven't yet been completed.
560735
561736#### Options
562737
563738See [Connection options](#connection-options)
564739
565−### `reshape generate-schema-query`
740+### `reshape schema-query`
566741
567742Generates the SQL query you need to run in your application before using the database. This command does not require a database connection. Instead it will generate the query based on the latest migration in the `migrations/` directory (or the directories specified by `--dirs`).
568743
744+If your application is written in Rust, we recommend using the [Rust helper library](https://github.com/fabianlindfors/reshape-helper/) instead.
745+
569746The query should look something like `SET search_path TO migration_1_initial_migration`.
570747
571748#### Options
572749
573−| Option | Default | Description |
574−| ------ | ------- | ----------- |
750+| Option | Default | Description |
751+| -------- | ------------- | --------------------------------------------------------------------------------------------------------------- |
575752| `--dirs` | `migrations/` | Directories to search for migration files. Multiple directories can be specified using `--dirs dir1 dir2 dir3`. |
576753
577754### Connection options
@@ -580,14 +757,14 @@ The options below can be used with all commands that communicate with Postgres.
580757
581758All options can also be set using environment variables instead of flags. If a `.env` file exists, then variables will be automatically loaded from there.
582759
583−| Option | Default | Environment variable | Description |
584−| ------ | ------- | -------------------- | ----------- |
585−| `--url` | | `DB_URL` | URL to your Postgres database |
586−| `--host` | `localhost` | `DB_HOST` | Hostname to use when connecting to Postgres |
587−| `--port` | `5432` | `DB_PORT` | Port which Postgres is listening on |
588−| `--database` | `postgres` | `DB_NAME` | Database name |
589−| `--username` | `postgres` | `DB_USERNAME` | Postgres username |
590−| `--password` | `postgres` | `DB_PASSWORD` | Postgres password |
760+| Option | Default | Environment variable | Description |
761+| ------------ | ----------- | -------------------- | ------------------------------------------- |
762+| `--url` | | `DB_URL` | URL to your Postgres database |
763+| `--host` | `localhost` | `DB_HOST` | Hostname to use when connecting to Postgres |
764+| `--port` | `5432` | `DB_PORT` | Port which Postgres is listening on |
765+| `--database` | `postgres` | `DB_NAME` | Database name |
766+| `--username` | `postgres` | `DB_USERNAME` | Postgres username |
767+| `--password` | `postgres` | `DB_PASSWORD` | Postgres password |
591768
592769## License
593770