Today who doesn’t know about Microsoft SQL Server. According to a report, the popularity of SQL Server grew faster than any other database product during 2016. Where SQL Server is so popular among worldwide users, on the other hand, it has a major drawback. Like any other database file, SQL Server database is not immune to corruption. You must restore SQL database objects in order to save them into a new database file. Sometimes it becomes a tedious task to repair SQL database if you don’t have sufficient technical knowledge. In case of minor corruption, you can use an easy manual trick. But if corruption is severe and you can’t fix it manually, it’s better to use a professional solution. It’s one of the best approaches to repair SQL database and to restore SQL database objects.
Microsoft SQL Server
SQL Server is a popular relational database management system (RDBMS) developed and provided by Microsoft Corporation. Being a database server, it’s primary function is to store and retrieve data as per the request by other software applications. Those applications may run either on the same computer or on another computer across a network (including the Internet). Microsoft SQL Server is available in multiple editions for different audiences and for different workloads. The workloads range from small single-machine applications to large Internet-facing applications with many concurrent users.
SQL Server uses SQL aka structured query language to communicate with a database file for requesting information from it. ANSI (American National Standards Institute) says that it’s the standard language for any relational database management system. The main tasks of SQL statements are to update data in a database and retrieve data from it. Other relational database management systems which use SQL are Oracle, Sybase, Access, Ingres, etc.
File Types used in MS SQL Server
There are three file types used in Microsoft SQL Server: MDF, NDF, and LDF.
- MDF is a primary database file in SQL Server having .mdf extension. An MDF contains user data and objects, such as indices, columns, views, functions, values, tables, keys, stored procedures, triggers, default values, etc. Also, it can store the startup information for the database. Each database in the SQL Server has one primary MDF file.
- NDF is a secondary database file in SQL Server having .ndf extension. You can create as much NDF files as you want. Though the primary function of NDF file is to spread data across multiple disks, it can also store user data.
- LDF is a LOG file in SQL Server having .ldf extension. It works as a backup file for SQL Server database. The primary function of a LOG file is to restore SQL database at the time of accidental deletion and/or corruption. An LDF file contains log information, and every database has at least one log file.
SQL Database Corruption
I’ve seen lots of people, especially database administrators (DBAs), ask this question, “how to prevent SQL Server database from going corrupt”. Since SQL Server database file is prone to corruption, you just can’t avoid corruption in SQL Server database. SQL database corruption is a very random problem faced by both SQL administrators as well as users. There are various reasons which can cause SQL database corruption. Since MDF files are the primary database files containing user data, any sort of corruption can corrupt the entire SQL database file. The most common reasons for corruption are:
- Unexpected changes in SQL Server accounts
- Accidental data deletion from the SQL database
- Corruption in the header part of the database
- Storage media corruption where SQL database file are stored
- Network failure when database is in working mode
- Using compressed folders to store SQL database
- Internal bugs in MS SQL Server program
- Software malfunction or collision
- Abruptly system shut down due to sudden power failure
How to restore SQL database?
Reasons are many for SQL database corruption, but solutions are only few. One of the best and most effective ways to restore SQL database is use backup. If you take regular backup of your SQL Server database, you can easily restore almost everything from corrupt MDF file. But if there’s no backup, how would you restore SQL database? I’ve mentioned earlier in this post that LDF files are the LOG files whose primary function is to restore SQL database at the time of accidental deletion and/or corruption. Well, you can use the LDF files here. If that doesn’t work, you should use the database console commands (DBCC): DBCC CHECKDB and DBCC DBREPAIR. To run these database console commands, you need to use Microsoft SQL Server Management Studio.
So just open it on your system, and follow these simple steps:
Step 1: On the toolbar, click New Query button to go to a new query page.
Step 2: Now you need to write the SQL scripts on the page:
EXEC sp_resetstatus [YourDatabase]; ALTER DATABASE [YourDatabase] SET EMERGENCY DBCC checkdb ([YourDatabase]) ALTER DATABASE [YourDatabase] SET SINGLE_USER WITH ROLLBACK IMMEDIATE DBCC DATABASE ([YourDatabase], REPAIR_ALLOW_DATA_LOSS) ALTER DATABASE [YourDatabase] SET MULTI_USER
Note: Replace the text YourDatabase with the original name of your database file.
Step 3: Finally, click Execute to start the repairing process.
This will take a few seconds to repair SQL database file. But if corruption is severe, the above manual trick may fail or not work. Thus, you should use an effective and reliable solution here. SQL Database Recovery software is the best solution available in the market to repair SQL database and to restore SQL database objects from corrupt MDF file.