sqlite3-helper
A promise based wrapper library for the work with sqlite3. It's intended for simple server-apps for nodejs and offer some new functions and a migration-system.
How to install
Like always
npm i sqlite3-helper
How to use
In every file you want access to a sqlite3 database simply require the library and use it right away in any async-function (or as a promise).
anyServerFile.js
const DB = ; async { let row = await ; console;}
To setup your database, create a sql
-file named 001-init.sql
in a migrations
-directory in the root-directory of your program.
~/migrations/001-init.sql
-- Up ( id INTEGER PRIMARY KEY, firstName TEXT NOT NULL, lastName TEXT NOT NULL, email TEXT NOT NULL); -- Down IF EXISTS `users`;
And that's it!
Node version < 10
If you work with a node version < 10 (having no support for async function *
async generator functions) use sqlite3-helper/no-generators
instead:
const DB = ; // ...
One global instance
A normal, simple application is mostly working with only one database. To make the class management more easy, this library does the access-control for you - mainly as a singleton. (But you can create a new instance to access other databases.)
The database loads lazy. Only when it's used for the first time, the database is read from the file, the migration is started and the journal-mode WAL is set. The default directory of the database is './data/sqlite3.db'
.
If you want to change the default-values, you can do this by calling the library once in the beginning of your server-code and thus setting it up:
index.js
const DB = ; // The first call creates the global instance with your settings
After that you can use the library without parameter:
anotherAPIFile.js
const DB = ; // a second call directly returns the global instanceasync { let row = await ; console;}
New Functions
This class implements shorthand methods for sqlite3.
async { // shorthand for db.prepare('SELECT * FROM users').all(); let allUsers = await ; // result: [{id: 1, firstName: 'a', lastName: 'b', email: 'foo@b.ar'},{},...] // result for no result: [] // shorthand for db.prepare('SELECT * FROM users WHERE id=?').get(userId); let row = await ; // result: {id: 1, firstName: 'a', lastName: 'b', email: 'foo@b.ar'} // result for no result: undefined // shorthand for db.prepare('SELECT * FROM users WHERE id=?').get(999) || {}; let id firstname = await ; // result: id = 1; firstName = 'a' // result for no result: id = undefined; firstName = undefined // shorthand for db.prepare('SELECT * FROM users WHERE id=?').pluck(true).get(userId); let email = await ; // result: 'foo@b.ar' // result for no result: undefined // shorthand for db.prepare('SELECT * FROM users').all().map(e => e.email); let emails = await ; // result: ['foo@b.ar', 'foo2@b.ar', ...] // result for no result: [] // shorthand for db.prepare('SELECT * FROM users').all().reduce((o, e) => {o[e.lastName] = e.email; return o;}, {}); let emailsByLastName = await ; // result: {b: 'foo@b.ar', c: 'foo2@b.ar', ...} // result for no result: {}}
Insert, Update and Replace
There are shorthands for update
, insert
and replace
. They are intended to make programming of CRUD-Rest-API-functions easier. With a blacklist
or a whitelist
it's even possible to send a request's query (or body) directly into the database.
Update
// const numberOfChangedRows = DB().update(table, data, where, whitelist = undefined) // simple use with a object as where and no whitelistawait // data from a request and a array as a where and only editing of lastName and firstName is allowedawait // update with blacklist (id and email is not allowed; only valid columns of the table are allowed) and where is a shorthand for ['id = ?', req.body.id]await
Insert and replace
// const lastInsertID = DB().insert(table, datas, whitelist = undefined)// const lastInsertID = DB().replace(table, datas, whitelist = undefined) // simple use with an object and no whitelistawait // inserting two usersawait // data from a request and only lastName and firstName are setawait // replace with blacklist (id and email is not allowed; only valid columns of the table are allowed)await // or insertWithBlackList
Try and catch
If you want to put invalid values into the database, the functions will throw an error. So don't forget to surround the functions with a try-catch
. Here is an example for an express-server:
const Router = const bodyParser = const DB = router
Migrations
The migration in this library mimics the migration system of the excellent sqlite by Kriasoft.
To use this feature you have to create a migrations
-directory in your root. Inside you create sql
-files that are separated in a up- and a down-part:
migrations/001-initial-schema.sql
-- Up (id INTEGER PRIMARY KEY, name TEXT); (id INTEGER PRIMARY KEY, categoryId INTEGER, title TEXT, CONSTRAINT Post_fk_categoryId FOREIGN KEY (categoryId) REFERENCES Category (id) ON UPDATE CASCADE ON DELETE CASCADE);INSERT INTO Category (id, name) VALUES (1, 'Business');INSERT INTO Category (id, name) VALUES (2, 'Technology'); -- Down Category Post;
migrations/002-missing-index.sql
-- Up ON Post (categoryId); -- Down Post_ix_categoryId;
The files need to be numbered. They are automatically executed before the first use of the database.
NOTE: For the development environment, while working on the database schema, you may want to set
force: true
(default false
) that will force the migration API to rollback and re-apply the latest migration over again each time when Node.js app launches. See "Global Instance".