Logical and physical consistency is being checked by DBCC CHECKDB, like index relationships, rows, allocation pages, system table referential integrity, and other formation verification. During this process if any above-mentioned checks fail, then you may receive errors. These errors could fluctuate from corruption of file like corrupted pages in memory, driver issues, underlying hardware system issue, or issue with SQL Server Engine. While working with SQL you may receive following DBCC CHECKDB command as mentioned below;

DBCC CHECKDB (mydb) executed by MYDOMAIN\theuser found 15 errors and repaired 0 errors. Elapsed time: 0 hours 0 minutes 0 seconds. Internal database snapshot has split point LSN = 00000026:0000089d:0001 and first LSN = 00000026:0000089c:0001. This is an informational message only. No user action is required.

If you have back-up you can restore from there but if you do not have any back-up then most recommended option would be to opt for some third party repair tool. And SQL Database File Repair Tool is best available for this purpose. It effectively scans and repairs DBCC CHECKDB error and also repairs damaged database and retrieve inaccessible objects in NDF and MDF database files. It restore and repair corrupt database files along with stored procedures, keys, views, triggers, indexes, tables, deleted records etc.