Backup Business Data

Each database can be corrupted by many causes, from human error, system crash, according to Murphy’s Law which states that if something can go wrong, then it will be even worse. From this reasoning it can be seen that surely at least once, our data will be harmed or that the data of our customers will be lost. From this premise can be seen easily as it is essential to a good backup strategy of our company data.
The frequency of backups should be directly proportional to the rate of change of the data, you can go to once or twice a day to once a week, in cases of large databases with very complex business realities you may need up to 10-12 rescues a day or more. In these cases we resort to backing up only changed data, as do the rescue of the entire database would be too expensive. To increase the security of the transaction is required to transfer the backup to external media or otherwise different from the one on which the data is located.
A backup is a copy of the entire database or a part of it performed at a given instant of time. A restore is a restore of a backup copy of the database, usually done after a loss of data. A log file is a record of transactions on the database, usually in it are filled with information of a transaction so that you can then replicate or undo (rollback). A recovery is an automatic data recovery after a problem occurred in the database, it is not to recover data from a backup, but to cancel and reapply a series of transactions that have been saved in a file logs. A checkpoint is a photograph of a database in the log file, in order to retrieve operations only after a certain point, resulting in faster data recovery.
The main problem related to a restore is to know if they have been restored to all corporate data or only a few, the main technique used to recover the entire database is called mirroring. This technique is to keep two or more copies of the same database on two or more different media, the positive aspects are that the data are unlikely to be lost, and above all it takes very little time to replace the database, the negative aspects can be attributed mainly to the high space backup that you must bear the burden. A technique less expensive in terms of resources uses the last saved log file and reapply the changes to the latest backup copy, in this case you are not sure of the complete data recovery and also take much more time.
In the case of databases that are based on files, such as Microsoft Access, the backup can be done by simply copying the file (.mdb) to external media, as in the case of my management software, but in the case of architecture-based DBMS client/server, the process is much more complicated. In the case of MS SQL Server there are tools that make up a programmed time, simply by setting them via the convenient wizard, while other data server must use the command line.