sqlcool2

Description:

sqlcool2

Sqlcool #

A database helper library for Sqflite. Forget about implementation details and focus on the business logic.

Simple: easy api for crud operations
Reactive: stream of changes, select bloc
Adaptative: plug custom models into the database

Check the documentation or the api doc for usage instructions
Simple crud #
Define the database schema #
import 'package:sqlcool/sqlcool.dart';

Db db = Db();
// define the database schema
DbTable category = DbTable("category")..varchar("name", unique: true);
DbTable product = DbTable("product")
..varchar("name", unique: true)
..integer("price")
..text("descripton", nullable: true)
..foreignKey("category", onDelete: OnDelete.cascade)
..index("name");
List<DbTable> schema = [category, product];
copied to clipboard
Initialize the database #
String dbpath = "db.sqlite"; // relative to the documents directory
try {
await db.init(path: dbpath, schema: schema);
} catch(e) {
rethrow;
}
copied to clipboard
Insert #
final Map<String, String> row = {name: "My item"};
try {
int id = await db.insert(table: "category", row: row)
} catch(e) {
rethrow;
}
copied to clipboard
Select #
try {
List<Map<String, dynamic>> rows = await db.select(
table: "product",
limit: 20,
columns: "id,name",
where: "name LIKE '%something%'",
orderBy: "name ASC",
);
} catch (e) {
rethrow;
}
copied to clipboard
Update #
try {
int numRowsUpdated = await db.update(table: "category",
row: row, where: "id=1");
} catch(e) {
rethrow;
}
copied to clipboard
Delete #
try {
await db.delete(table: "category", where: "id=3");
} catch(e) {
rethrow;
}
copied to clipboard
Join queries #
try {
final data = await db.join(
table: "product",
columns: "product.name,price,category.name as category_name",
joinTable: "category",
joinOn: "product.category=category.id");
} catch(e) {
rethrow;
}
copied to clipboard
Join on multiple tables #
try {
final data = db.mJoin(table: "product", joinsTables: <String>[
"category",
"manufacturer"
], joinsOn: <String>[
"product.category=category.id",
"product.manufacturer=manufacturer.id"
]);
} catch(e) {
rethrow;
}
copied to clipboard
Reactivity #
Changefeed #
A stream of database change events is available. Inspired by Rethinkdb
import 'dart:async';
import 'package:sqlcool/sqlcool.dart';

StreamSubscription changefeed;

changefeed = db.changefeed.listen((change) {
print("Change in the database:");
print("Query: ${change.query}");
if (change.type == DatabaseChange.update) {
print("${change.value} items updated");
}
});
// Dispose the changefeed when finished using it
changefeed.cancel();
copied to clipboard
Reactive select bloc #
The bloc will rebuild itself on any database change because of the reactive
parameter set to true:
import 'package:flutter/material.dart';
import 'package:sqlcool/sqlcool.dart';

class _PageSelectBlocState extends State<PageSelectBloc> {
SelectBloc bloc;

@override
void initState() {
super.initState();
this.bloc = SelectBloc(
table: "items", orderBy: "name", reactive: true);
}

@override
void dispose() {
bloc.dispose();
super.dispose();
}

@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(title: Text("My app")),
body: StreamBuilder<List<Map>>(
stream: bloc.items,
builder: (BuildContext context, AsyncSnapshot snapshot) {
if (snapshot.hasData) {
// the select query has not found anything
if (snapshot.data.length == 0) {
return Center(child: const Text("No data"));
}
// the select query has results
return ListView.builder(
itemCount: snapshot.data.length,
itemBuilder: (BuildContext context, int index) {
var item = snapshot.data[index];
return ListTile(
title: GestureDetector(
child: Text(item["name"]),
onTap: () => someFunction()),
);
});
} else {
// the select query is still running
return CircularProgressIndicator();
}
}),
);
}
}

class PageSelectBloc extends StatefulWidget {
@override
_PageSelectBlocState createState() => _PageSelectBlocState();
}
copied to clipboard
Database models #
New in 4.0.0: define models that have database methods. The main
advantage of this is to use only typed model data and avoid the
type conversions from maps for every query. It directly plugs custom
models into the database. Example:
In schema.dart:
final carTable = DbTable("car")
..varchar("name")
..integer("max_speed")
..real("price")
..integer("year")
..boolean("is_4wd", defaultValue: false)
..foreignKey("manufacturer", onDelete: OnDelete.cascade);

final manufacturerTable = DbTable("manufacturer")..varchar("name");
copied to clipboard
In car_model.dart:
import 'package:sqlcool/sqlcool.dart';
// the database schema
import 'schema.dart';
// another model
import 'manufacturer_model.dart';

class Car with DbModel {
Car(
{this.id,
this.name,
this.maxSpeed,
this.price,
this.year,
this.is4wd,
this.manufacturer});

/// define some class properties

final String name;
final int maxSpeed;
final double price;
final DateTime year;
final bool is4wd;
// this is a foreign key to another model
Manufacturer manufacturer;

/// [DbModel] required overrides

@override
int id;

/// the [Db] used
/// pass it your main db
@override
Db get db => db;

/// the table schema representation
/// check example/pages/dbmodels/schema.dart
@override
DbTable get table => carTable;

/// serialize a row to the database
@override
Map<String, dynamic> toDb() {
// we want the foreign key to be recorded
assert(manufacturer?.id != null);
final row = <String, dynamic>{
"name": name,
"max_speed": maxSpeed,
"price": price,
"year": year.millisecondsSinceEpoch,
"is_4wd": is4wd,
"manufacturer": manufacturer.id
};
return row;
}

/// deserialize a row from database
@override
Car fromDb(Map<String, dynamic> map) {
final car = Car(
id: map["id"] as int,
name: map["name"].toString(),
maxSpeed: map["max_speed"] as int,
price: map["price"] as double,
year: DateTime.fromMillisecondsSinceEpoch(map["year"] as int),
is4wd: (map["is_4wd"].toString() == "true"),
);
// the key will be present only with join queries
// in a simple select this data is not present
if (map.containsKey("manufacturer")) {
car.manufacturer =
Manufacturer().fromDb(map["manufacturer"] as Map<String, dynamic>);
}
return car;
}

/// Create a static join method for convenience

static Future<List<Car>> selectRelated({String where, int limit}) async {
final cars = List<Car>.from(
await Car().sqlJoin(where: where, limit: limit, verbose: true));
return cars;
}
}
copied to clipboard
Then use the models:
/// car is an instance of [Car]
await car.sqlInsert();
await car.sqlUpdate();
await car.sqlUpsert();
await car.sqlDelete();
final cars = Car.selectRelated(where: "speed>200");
// foreign keys are retrieved as model instances
print(cars[0].manufacturer.name);
copied to clipboard
Using this #

Sqlview: admin view and infinite list view
Kvsql: a type safe key/value store
Geopoint sql: sql operations for geospatial data