Hey guys,

Basically salesforce has provide us batch classes functionality to work on the async process in salesforce to handle a huge amount of data like upto 50 millions record, and to make the process easy of batch class. we have some thing called schedulable interface which is nothing but if you want to schedule a batch class or any other class you can implement this inteface and call the batch class by making the statement saying that 
Database.executebatch(pass the instance of respective batch class);

so there are two ways to schedule a batch class and they are:
1. through salesforce provide point and click process which available in saleforce schedule apex section.
2. through programatically where you need to specifically do it by using the system.schedulebatch method without having to implement the Schedulable interface.

so basically CronTrigger(it store the schedule information of scheduled job like nextfiretime,timesfired etc) and CronJobDetail(it contain the detail of schdeuled jon like job type nad name) are object and they use to get the count of Apex scheduled jobs. After the Apex job has been scheduled, you can obtain more information about it by running a SOQL query on CronTrigger and retrieving some fields, such as the number of times the job has run, and the date and time when the job is scheduled to run again,

PFB the example:
String jobID = system.schedule('job name', batchclassinstance, intervaltoexecutebatchinminutes);
CronTrigger ct = [SELECT TimesTriggered, NextFireTime FROM CronTrigger WHERE Id = :jobID];
OR
CronTrigger ct = [SELECT TimesTriggered, NextFireTime FROM CronTrigger WHERE Id = :sc.getTriggerId()]; wher sc is schedulablecontext variable.
OR
CronTrigger job = [SELECT Id, CronJobDetail.Id, CronJobDetail.Name, CronJobDetail.JobType FROM CronTrigger ORDER BY CreatedDate DESC LIMIT 1];
CronJobDetail ctd =  [SELECT Id, Name, JobType FROM CronJobDetail WHERE Id = :job.CronJobDetail.Id];

Regards
AS