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https://github.com/fukamachi/mito

An ORM for Common Lisp with migrations, relationships and PostgreSQL support
https://github.com/fukamachi/mito

common-lisp orm

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An ORM for Common Lisp with migrations, relationships and PostgreSQL support

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README 

        
# Mito



[![Build Status](https://github.com/fukamachi/mito/workflows/CI/badge.svg)](https://github.com/fukamachi/mito/actions?query=workflow%3ACI)

[![Quicklisp dist](http://quickdocs.org/badge/mito.svg)](http://quickdocs.org/mito/)



Mito is yet another object relational mapper, and it aims to be a successor of [Integral](https://github.com/fukamachi/integral).



* Supports MySQL, PostgreSQL and SQLite3

* Adds `id` (serial/uuid primary key), `created_at` and `updated_at` by default like Ruby's ActiveRecord

* Migrations

* DB schema versioning



## Warning



This software is still ALPHA quality. The APIs likely change.



This software should work fine with MySQL, PostgreSQL and SQLite3 on SBCL/Clozure CL.



## Usage



```common-lisp

(mito:connect-toplevel :mysql :database-name "myapp" :username "fukamachi" :password "c0mon-1isp")

;=> # {100691BFF3}>



(mito:deftable user ()

  ((name :col-type (:varchar 64))

   (email :col-type (or (:varchar 128) :null))))

;=> #



(mito:table-definition 'user)

;=> (#)



(mito:deftable tweet ()

  ((status :col-type :text)

   (user :col-type user)))

;=> #



(mito:table-definition 'tweet)

;=> (#)

```



### Connecting to DB



Mito provides the functions `connect-toplevel` and `disconnect-toplevel` to establish and sever a connection to RDBMS.



`connect-toplevel` takes the same arguments as `dbi:connect`: typically the driver-type, the database name to connect, user name and password.



```common-lisp

(mito:connect-toplevel :mysql :database-name "myapp" :username "fukamachi" :password "c0mon-1isp")

```



`connect-toplevel` sets `*connection*` to a new connection and returns it.



To use a connection lexically, just bind it:



```common-lisp

(let ((mito:*connection* (dbi:connect :sqlite3 :database-name #P"/tmp/myapp.db")))

  (unwind-protect (progn ...)

    ;; Ensure that the connection is closed.

    (dbi:disconnect mito:*connection*)))

```



In most cases `dbi:connect-cached` is a better option, since it reuses a connection for multiple threads.



```common-lisp

(let ((mito:*connection* (dbi:connect-cached :sqlite3 :database-name #P"/tmp/myapp.db")))

  (unwind-protect (progn ...)

    ;; Ensure that the connection is closed.

    ))

```



Use `connection-database-name` to get the name of the current connection, or of one named via parameter.



If you are using [clack](https://github.com/fukamachi/clack) as your webserver, A middleware is provided.



```common-lisp

(clack:clackup

  (lack:builder

    (:mito '(:sqlite3 :database-name #P"/tmp/myapp.db"))

    ...

    *app*))

```



### deftable macro



As Mito's dao table class is defined as a CLOS metaclass, a table class can be defined like this:



```common-lisp

(defclass user ()

  ((name :col-type (:varchar 64)

         :accessor user-name)

   (email :col-type (or (:varchar 128) :null)

          :accessor user-email))

  (:metaclass mito:dao-table-class))

```



`deftable`'s syntax is the same as that of `cl:defclass`. However, the definition is a little bit redundant.



`mito:deftable` is a thin macro, to allow definion of a table class with less typing.



For example, the above example can be rewritten, using `deftable` as follows.



```common-lisp

(mito:deftable user ()

  ((name :col-type (:varchar 64))

   (email :col-type (or (:varchar 128) :null))))

```



It adds `:metaclass mito:dao-table-class`, and adds default accessors that start with `-` by default, like `defstruct` does.



The prefix for accessors can be changed with the `:conc-name` class option:



```common-lisp

(mito:deftable user ()

  ((name :col-type (:varchar 64))

   (email :col-type (or (:varchar 128) :null)))

  (:conc-name my-))



(my-name (make-instance 'user :name "fukamachi"))

;=> "fukamachi"

```



If `:conc-name` is NIL, default accessors will NOT be defined.



### Class Definitions



In Mito, a class corresponding to a database table is defined by specifying `(:metaclass mito:dao-table-class)`.



```common-lisp

(defclass user ()

  ((name :col-type (:varchar 64)

         :accessor user-name)

   (email :col-type (or (:varchar 128) :null)

          :accessor user-email))

  (:metaclass mito:dao-table-class))

```



The above defines a Common Lisp normal class, except that it allows additional options.



```

(defclass {class-name} ()

  ({column-definition}*)

  (:metaclass mito:dao-table-class)

  [[class-option]])



column-definition ::= (slot-name [[column-option]])

column-option ::= {:col-type col-type} |

                  {:primary-key boolean} |

                  {:inflate inflation-function} |

                  {:deflate deflation-function} |

                  {:references {class-name | (class-name slot-name)}} |

                  {:ghost boolean}

col-type ::= { keyword |

              (keyword . args) |

              (or keyword :null) |

              (or :null keyword) }

class-option ::= {:primary-key symbol*} |

                 {:unique-keys {symbol | (symbol*)}*} |

                 {:keys {symbol | (symbol*)}*} |

                 {:table-name table-name} |

                 {:auto-pk auto-pk-mixin-class-name} |

                 {:record-timestamps boolean} |

                 {:conc-name conc-name}

auto-pk-mixin-class-name ::= {:serial | :uuid}

conc-name ::= {null | string-designator}

```



Note: the class automatically adds some slots -- a primary key named `id` if there is no primary key, `created_at` and `updated_at` for recording timestamps. To disable these behaviors, specify `:auto-pk nil` or `:record-timestamps nil` to defclass forms.



```common-lisp

(mito.class:table-column-slots (find-class 'user))

;=> (#

;    #

;    #

;    #

;    #)

```



This class inherits `mito:dao-class` implicitly.



```common-lisp

(find-class 'user)

;=> #



(c2mop:class-direct-superclasses *)

;=> (#)

```



This may be useful to define methods that can be applied for many or all table classes.



#### :col-type Options



The following are valid keywords for :col-type in the `deftable` definition above.



```common-lisp

:serial

:bigserial

:timestamptz

:integer

:bytea

:timestamp

:bigint

:unsigned

:int

:binary

:datetime

```



Besides the above keywords, there are other keywords that are valid, however they are dependent on the RDS and its version. 



An example of this is that `:json` and `:jsonb` work for PostgreSQL but don't work on an old version of MySQL which doesn't support those types.



A complete list of valid `:col-type` options is dependent on the database system. Here's a link for the current Data Types for:

- [PostgreSQL Data Types](https://www.postgresql.org/docs/current/datatype.html#DATATYPE-TABLE)

- [MySQL Data Types](https://dev.mysql.com/doc/refman/8.0/en/data-types.html)

- [SQLite3 Data Types](https://www.sqlite.org/datatype3.html)



The symbols are not defined directly in the system, rather they are the symbol equivalent of the string which is the name for the data type. Therefore, for any data type name, just preprend a colon to the name `:data-type` in order to use it as a `col-type`.



### Generating Table Definitions



```common-lisp

(mito:table-definition 'user)

;=> (#)



(sxql:yield *)

;=> "CREATE TABLE user (id BIGINT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY, name VARCHAR(64) NOT NULL, email VARCHAR(128), created_at TIMESTAMP, updated_at TIMESTAMP)"

;   NIL

```



### Creating DB tables



```common-lisp

(mapc #'mito:execute-sql (mito:table-definition 'user))



(mito:ensure-table-exists 'user)

```



### CRUD



```common-lisp

(defvar me

  (make-instance 'user :name "Eitaro Fukamachi" :email "[email protected]"))

;=> USER



(mito:insert-dao me)

;-> ;; INSERT INTO `user` (`name`, `email`, `created_at`, `updated_at`) VALUES (?, ?, ?, ?) ("Eitaro Fukamachi", "[email protected]", "2016-02-04T19:55:16.365543Z", "2016-02-04T19:55:16.365543Z") [0 rows] | MITO.DAO:INSERT-DAO

;=> #



;; Same as above

(mito:create-dao 'user :name "Eitaro Fukamachi" :email "[email protected]")



;; Getting the primary key value

(mito:object-id me)

;=> 1



;; Retrieving from the DB

(mito:find-dao 'user :id 1)

;-> ;; SELECT * FROM `user` WHERE (`id` = ?) LIMIT 1 (1) [1 row] | MITO.DB:RETRIEVE-BY-SQL

;=> #



(mito:retrieve-dao 'user)

;=> (#)



;; Updating

(setf (slot-value me 'name) "nitro_idiot")

;=> "nitro_idiot"



(mito:save-dao me)

;-> ;; UPDATE `user` SET `id` = ?, `name` = ?, `email` = ?, `created_at` = ?, `updated_at` = ? WHERE (`id` = ?) (2, "nitro_idiot", "[email protected]", "2016-02-04T19:56:11.408927Z", "2016-02-04T19:56:19.006020Z", 2) [0 rows] | MITO.DAO:UPDATE-DAO



;; Deleting

(mito:delete-dao me)

;-> ;; DELETE FROM `user` WHERE (`id` = ?) (1) [0 rows] | MITO.DAO:DELETE-DAO

(mito:delete-by-values 'user :id 1)

;-> ;; DELETE FROM `user` WHERE (`id` = ?) (1) [0 rows] | MITO.DAO:DELETE-DAO



;; Counting

(mito:count-dao 'user)

;-> 1

```



### Custom queries

Mito is at its core a rather thin wrapper around sxql and cl-dbi for converting sql results to special types and back. Most of the porcelain functions shown above are acutally implemented in just under 200 lines.



Given a plist which represents the result from the database, you can apply `make-dao-instance` To make it into a `dao-class` automatically doing inflation/deflation.



To run a custom query, use `retrieve-by-sql` which returns a list of plists.

```common-lisp

(mito:retrieve-by-sql

  (select (:user.*)

    (from :users)

    ;; Using a subquery to avoid a join and distinct

    ;; Make sure you actually test performance before doing this in production

    (where (:in :user.name

                (select (:poster)

                  (from :tweets)

                  (where (:> :tweets.likes 1000))

                  (returning :poster))))))

;=> ((:name "Shinmera" :email "[email protected]" :followers 200000)

;    (:name "Fukamachi" :email "[email protected]" :followers 100000) ...)

```



You can use `select-by-sql` if you want to automatically convert it to a class.



```common-lisp

(mito:select-by-sql 'user

  (select (:user.*)

    (from :users)

    (where (:in :user.name

                (select (:poster)

                  (from :tweets)

                  (where (:> :tweets.likes 1000))

                  (returning :poster))))))

;=> (# #)

```

The actual definition is basically `mapcar #'make-dao-instance` over the results of `retrieve-by-sql`



Finally `select-dao` provides the highest level API. This is usually what you need.

```common-lisp

(mito:select-dao 'user

  (where (:in :user.name

              (select (:poster)

                (from :tweets)

                (where (:> :tweets.likes 1000))

                (returning :poster)))))

;=> (# #)

```



It also provides neat facilities such as an `includes` clause so that you don't have to write out joins by hand (examples below).



### Relationship



To define a relationship, use `:references` on the slot:



```common-lisp

(mito:deftable user ()

  ((id :col-type (:varchar 36)

       :primary-key t)

   (name :col-type (:varchar 64))

   (email :col-type (or (:varchar 128) :null))))



(mito:deftable tweet ()

  ((status :col-type :text)

   ;; This slot refers to USER class

   (user-id :references (user id))))



;; The :col-type of USER-ID column is retrieved from the foreign class.

(mito:table-definition (find-class 'tweet))

;=> (#)

```



You can also specify another foreign class at `:col-type` to define a relationship:



```common-lisp

(mito:deftable tweet ()

  ((status :col-type :text)

   ;; This slot refers to USER class

   (user :col-type user)))



(mito:table-definition (find-class 'tweet))

;=> (#)



;; You can specify :USER arg, instead of :USER-ID.

(defvar *user* (mito:create-dao 'user :name "Eitaro Fukamachi"))

(mito:create-dao 'tweet :user *user*)



(mito:find-dao 'tweet :user *user*)

```



The latter example allows you to create/retrieve `TWEET` by a `USER` object, not a `USER-ID`.



Mito doesn't add foreign key constraints for referring tables, since I'm not sure it's still handful while using with ORMs.



### Inflation/Deflation



Inflation/Deflation is a function to convert values between Mito and RDBMS.



```common-lisp

(mito:deftable user-report ()

  ((title :col-type (:varchar 100))

   (body :col-type :text

         :initform "")

   (reported-at :col-type :timestamp

                :initform (local-time:now)

                :inflate #'local-time:universal-to-timestamp

                :deflate #'local-time:timestamp-to-universal))

  (:conc-name report-))

```



### Eager loading



One of the pains in the neck to use ORMs is the "N+1 query" problem.



```common-lisp

;; BAD EXAMPLE



(use-package '(:mito :sxql))



(defvar *tweets-contain-japan*

  (select-dao 'tweet

    (where (:like :status "%Japan%"))))



;; Getting names of tweeted users.

(mapcar (lambda (tweet)

          (user-name (tweet-user tweet)))

        *tweets-contain-japan*)

```



This example sends a query to retrieve a user, like "SELECT * FROM user WHERE id = ?" for each iteration.



To prevent this performance issue, add `includes` to the above query, which sends only a single WHERE IN query instead of N queries:



```common-lisp

;; GOOD EXAMPLE with eager loading



(use-package '(:mito :sxql))



(defvar *tweets-contain-japan*

  (select-dao 'tweet

    (includes 'user)

    (where (:like :status "%Japan%"))))

;-> ;; SELECT * FROM `tweet` WHERE (`status` LIKE ?) ("%Japan%") [3 row] | MITO.DB:RETRIEVE-BY-SQL

;-> ;; SELECT * FROM `user` WHERE (`id` IN (?, ?, ?)) (1, 3, 12) [3 row] | MITO.DB:RETRIEVE-BY-SQL

;=> (# # #)



;; No additional SQLs will be executed.

(tweet-user (first *))

;=> #

```



### Migrations



```common-lisp

(ensure-table-exists 'user)

;-> ;; CREATE TABLE IF NOT EXISTS "user" (

;       "id" BIGSERIAL NOT NULL PRIMARY KEY,

;       "name" VARCHAR(64) NOT NULL,

;       "email" VARCHAR(128),

;       "created_at" TIMESTAMP,

;       "updated_at" TIMESTAMP

;   ) () [0 rows] | MITO.DAO:ENSURE-TABLE-EXISTS



;; No changes

(mito:migration-expressions 'user)

;=> NIL



(mito:deftable user ()

  ((name :col-type (:varchar 64))

   (email :col-type (:varchar 128)))

  (:unique-keys email))



(mito:migration-expressions 'user)

;=> (#

;    #)



(mito:migrate-table 'user)

;-> ;; ALTER TABLE "user" ALTER COLUMN "email" TYPE character varying(128), ALTER COLUMN "email" SET NOT NULL () [0 rows] | MITO.MIGRATION.TABLE:MIGRATE-TABLE

;   ;; CREATE UNIQUE INDEX "unique_user_email" ON "user" ("email") () [0 rows] | MITO.MIGRATION.TABLE:MIGRATE-TABLE

;-> (#

;    #)

```



SQLite3 migration creates temporary tables with pre-migration data. To delete them after migration is complete set

`mito:*migration-keep-temp-tables*` to `nil`. It has no effect on other drivers.



#### Auto migrations



If `mito:*auto-migration-mode*` is set to `t`, and you are connected to a database, Mito will run migrations after

each change to model definitions.



### Schema versioning



```

$ ros install mito

$ mito

Usage: mito command [option...]



Commands:

    generate-migrations

    migrate

    migration-status



Options:

    -t, --type DRIVER-TYPE          DBI driver type (one of "mysql", "postgres" or "sqlite3")

    -d, --database DATABASE-NAME    Database name to use

    -u, --username USERNAME         Username for RDBMS

    -p, --password PASSWORD         Password for RDBMS

    -s, --system SYSTEM             ASDF system to load (several -s's allowed)

    -D, --directory DIRECTORY       Directory path to keep migration SQL files (default: "/Users/nitro_idiot/Programs/lib/mito/db/")

    --dry-run                       List SQL expressions to migrate

    -f, --force                     Create a new empty migration file even when it's unnecessary.

```



#### Example



```

mito --database postgres --username fukamachi --pasword c0mmon-l1sp

```



### Inheritance and Mixin



A subclass of DAO-CLASS is allowed to be inherited. This may be useful when you need classes that have similar columns:



```common-lisp

(mito:deftable user ()

  ((name :col-type (:varchar 64))

   (email :col-type (:varchar 128)))

  (:unique-keys email))



(mito:deftable temporary-user (user)

  ((registered-at :col-type :timestamp)))



(mito:table-definition 'temporary-user)

;=> (#)

```



If you need a 'template' for tables, not related to any specific database table, you can use `DAO-TABLE-MIXIN`:



```common-lisp

(defclass has-email ()

  ((email :col-type (:varchar 128)

          :accessor object-email))

  (:metaclass mito:dao-table-mixin)

  (:unique-keys email))

;=> #



(mito:deftable user (has-email)

  ((name :col-type (:varchar 64))))

;=> #



(mito:table-definition 'user)

;=> (#)

```



* [mito-attachment](https://github.com/fukamachi/mito-attachment)

* [mito-auth](https://github.com/fukamachi/mito-auth)



### Triggers



Since `insert-dao`, `update-dao` and `delete-dao` are defined as generic functions, you can define `:before`, `:after` or `:around` methods on those.



```common-lisp

(defmethod mito:insert-dao :before ((object user))

  (format t "~&Adding ~S...~%" (user-name object)))



(mito:create-dao 'user :name "Eitaro Fukamachi" :email "[email protected]")

;-> Adding "Eitaro Fukamachi"...

;   ;; INSERT INTO "user" ("name", "email", "created_at", "updated_at") VALUES (?, ?, ?, ?) ("Eitaro Fukamachi", "[email protected]", "2016-02-16 21:13:47", "2016-02-16 21:13:47") [0 rows] | MITO.DAO:INSERT-DAO

;=> #

```



## Installation



```common-lisp

(ql:quickload :mito)

```



Or, with Roswell:



```

ros install mito

```



## See Also



* [CL-DBI](https://github.com/fukamachi/cl-dbi)

* [SxQL](https://github.com/fukamachi/sxql)



## Author



* Eitaro Fukamachi ([email protected])



## Copyright



Copyright (c) 2015 Eitaro Fukamachi ([email protected])



## License



Licensed under the LLGPL License.