mysql-json-schema

mysql-json-schema

Leer en Español.

With this module, you can extract the schema of a MySql database in JSON format, including the relations between tables. It is also possible to extract relations by 'naming convention'.

Installation

npm install mysql-json-schema --save-dev

API

List of arguments:

• user: database user required
• password: database password required
• host: database host required
• database: database name required
• outputFolder: ouput folder for generated files required
• discoverRelations: defaut: false, if set this as true, the relations will be looked for by aliases or 'naming convention' like <prefix><tableName> or <tableName><sufix>, where by default prefix = 'id_' and sufix = '_id'. Ie: phones.contact_id will be generate a relation from phones table by the contact_id field to the key field of contact table.
• extractRelations: default: true, extract relations that are defined in MySql.
• aliases: default: [], are necessaries when you have some specific cases of names for the fields that are related, ie: [{localTable: 'phones', localField: 'phone_type', foreignTable: 'phone_types', foreignField: 'id'}],
• ignoreDefaultNames: default: false, you should set it in true if you want to discoverRelations only by aliases, not using prefix or sufix
• prefix: default: 'id_ ', prefix for foreign key, ie: , if prefix = 'id_', and tableName = 'table1' then id_table1 will be mapped as a foreign key.
• sufix: default: '_id', sufix for foreign key, ie: , if sufix = '_id', and tableName = 'table1' then table1_id will be mapped as a foreign key.

---

Signature	Description
CreateConnection({ host, user, password, database })	Creates a connection to a database (don't forget to close it).
CreateConnectionAsync({ host, user, password, database })	Creates a connection to a database and returns a promise (don't forget to close it).
GetSchema(connection)	Returns schema without relations.
GetSchemaWithRelations(connection)	Returns schema with relations.
GetSchemaWithRelationsByFieldNames(connection, aliases, ignoreDefaultNames, prefix, sufix)	Returns schema with relations by field names.
GetTableList(connection)	Returns the database's tables list.
GetFieldsFromTable(connection, tableName)	Returns the field list from a table.
GetRelationsFromTable(connection, tableName)	Returns the relations from a specific table pointing to others.
GetRelationsToTable(connection, tableName)	Returns the relations from other tables pointing to specific one.
GetRelationsFromTableByFieldNames({ tableName, schema, aliases, ignoreDefaultNames, prefix, sufix })	Look for the relationships where a table points to other tables.
GetRelationsToTableByFieldNames({ tableName, schema, aliases, ignoreDefaultNames, prefix, sufix })	Look for relationships where the tables are pointing to a specific one.
ExportSchemaToFiles(args)	Exports a schema to outputPath on separate files(No connection required).
ExportSchemaToFile(args)	Exports a schema to outputFolder on a file(No connection required).

Code Example

Here an example of an exported schema in JSON format. And here an sql script to create that schema.

Our schema has three tables, contacts <--- (contact_id) --- phones --- (phone_type) ---> phone_types please check the sql script for details.

A quick example to export the schema to some folder.

import mysql from 'mysql-json-schema';
mysql.ExportSchemaToFiles({
    user: 'root',
    password: 'root',
    host: 'localhost',
    database: 'yourdb',
    outputFolder: 'some folder'
});

---

How to work with the JSON schema:

import mysql from 'mysql-json-schema';
const connection = mysql.CreateConnection({
    user: 'root',
    password: 'root',
    host: 'localhost',
    database: 'yourdb'
});
connection.connect();
mysql.GetSchemaWithRelations(connection)
    .then((schema) => {
        connection.end(); /* After using the connection, it must be closed. */
        const tableNames = Object.keys(schema.tables);
        tableNames.forEach(function (tableName) {
            const table = schema.tables[tableName];
            table.fields.forEach(function (field) {
                field.Field; // Field name
                field.Type; // Field type, ej: int(11)
                field.Null; // is nullable? ej: false
                field.Key; // ej: PRI
                field.Default; // default value
                field.Extra; // extra, ej: auto_increment
            });
            
            // Relations:
            table.relationsFromTable.forEach(function (relation) {
                relation.localField;
                relation.foreignTable;
                relation.foreignField;
            });
            
            table.relationsToTable.forEach(function (relation) {
                relation.localField;
                relation.foreignTable;
                relation.foreignField;
            });
        });
    });

---

Advanced look for relations, by field name:

import lodash from 'lodash';
import mysql from 'mysql-json-schema';
const args = {
    user: 'root',
    password: 'root',
    host: 'localhost',
    database: 'yourdb',
    outputFolder: 'somefolder',
    discoverRelations: true,
    extractRelations: false,
    aliases: [{localTable: 'phones', localField: 'phone_type', foreignTable: 'phone_types', foreignField: 'id'}],
    ignoreDefaultNames: false,
    prefix: 'id_',
    sufix: '_id'
};

mysql.ExportSchemaToFile(args); // if you want to export the schema directly to a file

// if you want to manipulate the schema
const connection = mysql.CreateConnection(args);
connection.connect();
mysql.GetSchema(connection)
    .then((schema) => {
        connection.end(); // close the connection
        const { discoverRelations, extractRelations, aliases, ignoreDefaultNames, prefix, sufix } = args;

        const aliasesFromThisTable = lodash.filter(aliases, (a) => a.localTable === 'phones'); // only need aliases from this table
        const relationsFrom = mysql.GetRelationsFromTableByFieldNames('phones', schema, aliasesFromThisTable, ignoreDefaultNames, prefix, sufix);
        console.log('Relations From phones');
        console.log(JSON.stringify(relationsFrom, null, 4));

        const aliasesToThisTable = lodash.filter(aliases, (a) => a.foreignTable === 'contacts'); // only need aliases to this table
        console.log('Relations To contacts');
        const relationsTo = mysql.GetRelationsToTableByFieldNames('contacts', schema, aliasesToThisTable, ignoreDefaultNames, prefix, sufix);
        console.log(JSON.stringify(relationsTo, null, 4));
    });

expected output:

Relations From phones
[
    {
        "localField": "contacts_id",
        "foreignTable": "contacts",
        "foreignField": "id"
    },
    {
        "localField": "phone_type",
        "foreignTable": "phone_types",
        "foreignField": "id"
    }
]
Relations To contacts
[
    {
        "localField": "id",
        "foreignTable": "phones",
        "foreignField": "contacts_id"
    }
]

---

Test

npm test

License

This software is released under the MIT License.