Use a MySQL database as a JSON document store (in Node)
This package provides an interface to a MySQL database, accessing data as JSON documents.
Queries are performed using JSON Schema to provide powerful search constraints on the data.
You generate a class using a config object. This config file specifies:
var myJson = require('my-json');
var TestClass = myJson({
table: 'TestTable',
keyColumn: 'integer/id',
columns: {
'integer/id': 'id',
'string/name': 'name',
'json': 'json_remainder'
}
});
This will work with a table structure like:
+----------+----------+----------------+
| id | name | json_remainder |
+----------+----------+----------------+
| 5 | blah | {"extra": 20} |
+----------+----------+----------------+
Columns of the json
type contain a JSON representation of any properties that are not accounted-for by any of the other columns. This table row therefore corresponds to a document like:
{
"id": 5,
"name": "blah",
"extra": 20
}
Currently it only supports plain objects (taken from a single row), but support for arrays (as table joins) is planned - see the PHP equivalent JSON Store for what's planned.
For all the operations, you can either supply a MySQL connection each time, or you can bind a connection.
Binding also creates a cache - this means that if the same document is returned by two different queries, then they will be represented by the same instance. These caches are expected to be temporary (perhaps once per request for a web-server).
var mysql = require('mysql');
var connection = mysql.createConnection({...});
var BoundTestClass = TestClass.cacheWith(connection);
TestClass.open(connection, 5, function (err, result) {...});
BoundTestClass.open(5, function (err, result) {...});
The arguments given to open()
should match (length and order) the columns specified in the config's "keyColumn"
(or "keyColumns"
) property.
If found, result
will be an instance of the appropriate class - otherwise, it will be undefined
.
var schema = {
type: "object",
properties: {
"id": {"enum": [5]}
}
};
TestClass.search(connection, schema, function (err, results) {...});
BoundTestClass.search(schema, function (err, results) {...});
Currently, the only schema keywords supported are properties
and enum
, but support for all validation keywords is planned.
TestClass.save(connection, testObj, function (err, results) {...});
BoundTestClass.save(testObj, function (err, results) {...});
Creation is performed by saving an object that is missing a key column:
var newObj = new TestClass();
newObj.name = 'test';
TestClass.save(connection, testObj, function (err, results) {...});
// or:
BoundTestClass.save(testObj, function (err, results) {...});
newObj.id; // populated using the auto-increment, if there is one
TestClass.remove(connection, testObj, function (err, results) {...});
BoundTestClass.remove(testObj, function (err, results) {...});
For the above methods/functions that take a callback as a final argument, the callback can be omitted.
If the callback is omitted, then a Promise object is returned instead (from this module).