var Dml = require ('./dml');

/**
 * The equivalent of a SQL update.
 */
module.exports = new Class
({
	Extends: Dml

	,render: function (batch)
	{
		var sql;
		var n;
		
		sql = 'UPDATE ' + this.renderTarget (batch) + ' SET ';
		
		for (n = 0; n < this.field.length; n++)
		{
			if (n > 0)
				sql += ', ';
			sql += this.field[n].render () + ' = ' + this.expr[n].render(batch);
		}
		
		if (this.where)
			sql += ' WHERE ' + this.where.render (batch);
			
		sql += ' LIMIT 1';	// Only for security.
			
		return sql;
	}
});