knex/clients/server/mysql.js
2013-11-25 02:00:12 -05:00

70 lines
2.6 KiB
JavaScript

// MySQL
// -------
// Other dependencies, including the `mysql` library,
// which needs to be added as a dependency to the project
// using this database.
var _ = require('lodash');
var mysql = require('mysql');
// All other local project modules needed in this scope.
var ServerBase = require('./base').ServerBase;
var Helpers = require('../../lib/helpers').Helpers;
var Promise = require('../../lib/promise').Promise;
var grammar = require('./mysql/grammar').grammar;
var schemaGrammar = require('./mysql/schemagrammar').schemaGrammar;
// Constructor for the MySQLClient.
exports.Client = ServerBase.extend({
dialect: 'mysql',
// Attach the appropriate grammar definitions onto the current client.
attachGrammars: function() {
this.grammar = grammar;
this.schemaGrammar = schemaGrammar;
},
// Runs the query on the specified connection, providing the bindings
// and any other necessary prep work.
runQuery: function(connection, sql, bindings, builder) {
return Promise.bind(this).then(function() {
if (!connection) throw new Error('No database connection exists for the query');
if (builder.flags.options) sql = _.extend({sql: sql}, builder.flags.options);
if (builder._source === 'SchemaBuilder') {
return this.advancedQuery(connection, sql, builder);
}
return sql;
}).then(function(sql) {
return Promise.promisify(connection.query, connection)(sql, bindings);
}).bind();
},
// Get a raw connection, called by the `pool` whenever a new
// connection needs to be added to the pool.
getRawConnection: function() {
var connection = mysql.createConnection(this.connectionSettings);
return Promise.promisify(connection.connect, connection)().yield(connection);
},
// Used to explicitly close a connection, called internally by the pool
// when a connection times out or the pool is shutdown.
destroyRawConnection: function(connection) {
connection.end();
},
// Used to check if there is a conditional query needed to complete the next one.
advancedQuery: function(connection, sql, builder) {
if (sql.indexOf('alter table') === 0 && sql.indexOf('__datatype__') === (sql.length - 12)) {
var newSql = sql.replace('alter table', 'show fields from').split('change')[0] + ' where field = ?';
return Promise.promisify(connection.query, connection)(newSql, [builder.commands[builder.currentIndex].from]).then(function(resp) {
var column = resp[0];
// Set to the datatype we're looking to change it to...
return sql.replace('__datatype__', column[0].Type);
});
}
return sql;
}
});