Do you encounter Input/Output (I/O) errors while accessing a MS SQL Server database? Are you unable to run queries on or access data from MDF (Master Database File)? This behavior indicates system or hardware problems with SQL Server that corrupt the database and renders it inaccessible. It leads to critical data loss situations. In order to extract data from Microsoft SQL Server in such situations, you need to opt for SQL Recovery solutions.

Hardware and system problems in SQL Server are generally indicated by an error message, similar to the following one:

"Error 823 I/O error detected during at offset in file ''"

You come across this error message when SQL Server attempts to read data from and write data to the database files. Format of this error message can be different, depending upon the version of SQL Server.

Cause

You come across this error message, if any of the below conditions are true: Operating system error. I/O logical check failure. MS SQL Server database corruption.

If any of the above situations occur, it becomes essential to perform SQL Server Recovery by resolving it, to retrieve inaccessible data.

Solution

Try out the below things to fix up this issue, as per the cause of the the problem:

Operating system error: The read Windows API (Application Programing Interface) call or the write API call is unsuccessful and MS SQL Server experiences operating system errors, which is related to Windows API call. Run operating system integrity checking tools. Following is the example of operating system error:

"2003-07-28 09:01:27.38 spid75 Error: 823, Severity: 24, State: 2 2003-07-28 09:01:27.38 spid75 I/O error 1117 (The request could not be performed because of an I/O device error.) detected during read at offset 0x0000002d460000 in file 'e:\program files\Microsoft SQL Server\mssql\data\mydb.MDF'" I/O check failure: If specified logical data checks are unsuccessful, you may encounter this problem. Run DBCC CHECKDB to solve this issue. Database corruption: Restore the database from recent backup. If the backed is unusable, Recover SQL database through third-party applications.

The SQL Database Recovery software are powerful enough to handle most of the database corruption issues. The applications use high-end scanning methods to ensure absolute recovery. They are incorporated with rich graphical user interface to provide quick and easy recovery.

SQL Recovery is the most advanced and powerful utility that is able to effectively handle all database corruption scenarios. The software works well with Microsoft SQL Server 2008, 2005, and 2000. It restores all MDF file objects such as tables, reports, forms, constraints, stored procedures, triggers, data types, and more.

Database corruption after unexpected system shutdown is a common scenario happened to almost all of us. The database becomes unmountable, further resulting in inaccessibility of records, after being corrupted. In most of these situations, you receive an error message that describes the exact cause of corruption, and sometimes its resolution too. However, if the resolution provided in the error message works, then there is no need to worry. But if in case, the resolution fails, then the best way to overcome database corruption is by restoring the data from an updated backup. Unavailability of a valid backup leaves you with no option, but to use advanced third-party

application to repair the database.

Consider a practical scenario, where your database unexpectedly stops and restarts again. On the restart, the database does not mount, and you view the below error messages in the error log file:

"DateTimeSPID Error: 602, Severity: 21, State: 30. DateTimeSPID Could not find an entry for table or index with partition ID 491897996509184 in database 2. This error can occur if a stored procedure references a dropped table, or metadata is corrupted. Drop and re-create the stored procedure, or execute DBCC CHECKDB. DateTimeSPID Error: 9001, Severity: 21, State: 5. DateTimeSPID The log for database 'msdb' is not available. Check the event log for related error messages. Resolve any errors and restart the database. DateTimeSPID Error: 3449, Severity: 21, State: 1. DateTimeSPID SQL Server must shut down in order to recover a database (database ID 1). The database is either a user database that could not be shut down or a system database. Restart SQL Server. If the database fails to recover after another startup, repair or restore the database."

Cause:

Unexpected shutdown could be caused when SQL Server is unable to handle duplicate partition Ids, which are produced in tempdb database.

Resolution:

To resolve database corruption, you will need to opt for advanced MS SQL Repair tool. These tools use advanced scanning methods to repair your database. Such SQL Repair tools do not require any technical skills to perform database repair.

Restoration of data from an updated database backup allows you to overcome almost all SQL Server database corruption scenarios. It is therefore, always recommended to maintain a systematic database backup on some other storage media as well. While restoration of data is an easy process, it might result into an error message, which prevents you from restoration of the database. In such situations, an easy way is to restore the data from any other updated database backup. However if in case, no other backup is available or backup falls short to restore the data, then you will need to opt for advanced third-party

application.

Consider a practical scenario, where you encounter the underneath error message while restoration of data:

"Msg 8967, Level 16, State 216, Server , Line 2 An internal error occurred in DBCC which prevented further processing. Please contact Customer Support. DBCC results for ''. Msg 8921, Level 16, State 1, Server , Line 1 Check terminated. A failure was detected while collecting facts. Possibly tempdb out of space or a system table is inconsistent. Check previous errors."

On viewing the your SQL Server log, you view another error message:

"2007-05-26 07:13:49.21 spid58 DBCC encountered a page with an LSN greater than the current end of log LSN () for its internal database snapshot. Could not read page (file id:page id), database '), LSN = (), type = 32, isInSparseFile = 1. Please re-run this DBCC command."

While the restoration process halts, the data stored in the database becomes inaccessible.

Cause:

The above error message primarily occurs when the DBCC CHECKDB command is unable to serve the required checks that confirm the consistency of your database. These checks could not be performed due to numerous reasons, such as SQL Server database corruption, metadata structure damage, and more.

Resolution:

To resolve the above error message and to access the database records, you will need to use advanced SQL Repair tool that provides comprehensive repair of corrupt database. Such SQL Repair tools are non-destructive in nature as they do overwrite or modify the original records of the database.

The main purpose of DBCC CHECKDB command in MS SQL is to check the integrity (logical and physical) of all the specified database objects. The command performs three operations (DBCC CHECKALLOC, DBCC CHECKTABLE, and DBCC CHECKCATALOG) to comprehensively repair the corrupted database. While the repair command repairs your database in most situations, it might fail to repair in case of damage of critical system tables. In such circumstances, an easy way is to restore the data from an updated database backup. But in case of absence of an updated backup or the backup file itself getting corrupted, then you will need to search for advanced

application that can repair your database.

Consider a practical situation, where you receive the below error message when you attempt to mount your database:

"Database ID DB_ID, object 'OBJNAME' (ID O_ID). Loop in data chain detected at P_ID."

After the above error message pops up, your database becomes unmountable. Furthermore, the data stored in your database becomes inaccessible.

Cause:

The root cause for the occurrence of the above error message is corruption in metadata structure of SQL database. Corruption can occur by both logical or physical reasons.

Resolution:

To resolve the above error message and to access the database records, follow the below three measures:

Swap the physically damaged system component with a new component. Execute DBCC CHECKDB command (with appropriate repair clause.) Restore the data from an updated database backup.

Out of the above three measures, the first measure provides complete resolution from the physical damage situations. The other two measures fail to perform in case the database is severely corrupted or there is no backup available. In such situations, the only alternative left is advanced SQL Repair software.

Such SQL Recovery tools ensure complete repair of most corrupted SQL databases. These applications come with interactive user documentation that makes the database user to easily understand the repair process. These repair tools are non destructive in nature.

Mapping of MS SQL Server database is performed over a group of operating system files. The information related to data and logs is kept in different files, while single files are handled only by one database. The collections of all these files is known as filegroup. Two major functions that every filegroup performs are placement of data and administrative tasks. Corruption in any of the filegroups primarily results in unmountability of your database, which further results in inaccessibility of database records. To access your records after your SQL Server database becomes unmountable, a simple way is to restore the data from an updated database backup. But in weird situations where you have not created any backup or backup falls short to restore the records, you will need to start searching for an advanced third-party

application.

Picture a scenario where you attempt to access the data saved in one of your SQL Server database, an you receive below error message:

"IAM page P_ID for object ID O_ID, index ID I_ID controls pages in filegroup FG_ID1, that should be in filegroupFG_ID2."

Database records stored in your database do not appear because the above error message does not allow the database to mount. In addition, you repeatedly receive the above error message each time you attempt to access the database records.

Cause:

The root cause for occurrence of the above error message is damage of filegroup. Corruption can occur either due to logical or physical reasons.

Resolution:

Below are two measures that allow you to access database records:

Swap the physically damage component with a new component to overcome all physical damage issues. Run DBCC CHECKDB command to surmount all logical issues.

Although the above resolutions prove successful in most cases, the possibility overcoming all logical corruption scenarios by using DBCC CHECKDB command is slightly less. In such situations, a powerful SQL Database Recovery application enables you to repair your corrupt database and access it records. Such SQL Repair tools use advance repairing procedures to thoroughly scan and repair the corrupt database.

DBCC CHECKTABLE command in SQL Server database is used to check your database table for errors. The command creates a mini dump file in the SQL Server Log Directory whenever it detects that the table is corrupt or damaged. If you wish to access the records saved in the table in such scenarios, then you will need to restore the data from an updated backup. However, if in case the backup is not available or backup falls short to restore the table records, then you will need to search for advanced

application.

As a practical case, you view the below error message in mini dump file after you run DBCC CHECKTABLE command to check your table:

"CHECKTABLE processing of object ID O_ID, index ID I_ID encountered page P_ID, slot S_ID twice. Possible internal error or allocation fault."

Your table records become inaccessible after the above error message appears.

Cause:

The root cause for the above error message is encountering of Page P_ID during the course of scanning.

Note: Table corruption can occur either due to logical or physical damage.

Resolution:

To resolve the above error message and to access table records, you will need to follow the below steps:

Restore the data from an complete backup. In case of physical damage, change the damaged system component. For logical corruption scenarios, run DBCC CHECKDB using appropriate repair clause.

Swapping the damaged system component provides complete resolution from all physical damage scenarios. The other two resolution fail to perform under tow scenarios:

The backup is unavailable. Severe Corruption of the database.

To repair your corrupted database in the above scenarios, you will need to search for an efficient SQL Database Repair tool. These MS SQL Repair applications are developed by talented data recovery experts and repair databases after almost all logically corrupted SQL databases. These repair tools use high-end scanning methods to repair and restore the recovered database components on default or user-defined destination. These read only nature of these database repair applications ensure risk-free repair of database, leaving the original database file untouched and unmodified.

In SQL Server database, rows of a table are divided and stored into a series of partitions. These rows can either be saved in heap or B-tree structure. In heap tree structure, the table does not contain any Index and the forward row always points back to the forwarding row. However, in B-tree structure the rows are saved in accordance to the Index values. Corruption in metadata structure of your SQL database results in changing the values of these rows, thereby resulting in inaccessibility of all database records. An easy way to surpass such corruption scenarios is by using restoring the data from an updated backup. But, the possibility of backup being corrupted or damaged always exist. In such situations, an ideal way is to repair your database by using an effective

software.

Consider a scenario, where the underneath error message pops up every time you attempt to mount your database:

"Forwarded row mismatch: Object ID O_ID, page P_ID1, slot S_ID1 points to forwarded row page P_ID2, slot S_ID2; the forwarded row points back to page P_ID3, slot S_ID3."

Your database records become inaccessible after the above error message appears.

Cause:

The main reason of the above error message is that the forwarded row (S_ID2 on page P_ID2) instead of pointing to forwarding row (S_ID1 on page P_ID1), is pointing to the wrong row.

Note: The above case can occur due to both logical and physical corruption scenarios.

Resolution:

The resolution for the above error message is mentioned below:

Swap the system component that is damaged with a new component. Execute DBCC CHECKDB command.

While the former resolution to overcome hardware related issues is perfect, the later solution might fail to resolve logical corruption issues. For complete and systematic resolution in all logical corruption scenarios, you will need to opt for advanced SQL Database Repair tool. Such tools provide maximum MS SQL Repair by employing high end scanning and repairing algorithms. These tools are non-destructive and perform recovery without making any changes in the original database file.

A commit transaction in SQL Server is primarily used to make all the changes permanent which you performed since the start of transaction. Once you run the commit statement, all the resources held by the transaction are freed and the value for TRANCOUNT is set to "0". Interruption while processing of commit transaction can result into making your database suspect. In such situations, your database becomes unmountable and the records stored in it become inaccessible. For complete access of database records after it has been corrupted, you will need to restore the data from an updated database backup. However, if the database backup is corrupted or unavailable, then you will need to use advanced third-party

application that can systematically repair your corrupted database.

A commit transaction can be halted due to below reasons:

A SQL Server CE application closes unexpectedly. Windows CE device is reset. SQL Server CE does not respond.

Your database is marked suspect after any of the above problem occurs. Furthermore, this leaves your database in an unrecoverable state. The above problems occur either due to power failure or an explicit reset during a transaction. Below are some prevention measures that enable you to minimize the effect of the problem:

Ensure that you have maintained a backup copy of your SQL Server CE database files. To prevent database users from performing an explicit reset while a data manipulation process is in progress, add a progress bar in your application. Always try to keep your transactions short.

Resolution:

To make your database records accessible, you will need to use Compact method. While the method repairs the database in many cases, chances of database corruption still exists. In such situations, the only way left to repair your database is by using advanced SQL Database Repair application.

These database repair utilities employ intensive scanning methods to repair your corrupted database and recover almost all database components. With highly-interactive user documentation, the MS SQL Repair software guides you through a complete repair process. The non-destructive software provides safe recovery of database components and provides an option to save them on default or new destination.

Data storage space in SQL database is primarily divided into numerous pages. Each page contains a 96-byte header that contains information related to page number, page type, ID, and free space. Corruption in metadata structure primarily results in failing to read the data stored on the page. This further results in making the data stored in the database inaccessible. In such situations, the data stored in the database can be accessed by restoring it from an updated backup. However, there have been instances where the backup has not been created or the backup file is corrupted due to various logical and physical factors. For accessing your database records under such circumstances, you will need to search for an advanced third-party Recover SQL application.

Consider a practical scenario, where you encounter the below error message when you attempt to mount your SQL database:

“Could not read and latch page P_ID with latch type TYPE. OPERATION failed.”

The above error message appears each time you attempt to access the database records. Furthermore, the above error message makes the database records inaccessible.

Cause:

The root cause for the occurrence of the above error message is the failure of page read due to any of the below reasons:

• The page is in repairing state.

• An indeterminate function is being performed on the page.

• The page might be read as a part of per checks of important system tables.

Note: The above scenarios can occur due to both logical and physical reasons.

Resolution:

To resolve the above error message and to execute your database records, you will need to

swap the damaged system component with a new one (for physical damages). For logical crash scenarios, you will need to run DBCC CHECKDB command (with correct repair clause).

Changing the damaged hardware component provides comprehensive solution to get rid of all hardware problems. But, in case of removing logical corruption scenarios, DBCC CHECKDB is not always a complete solution. For permanent resolution of all corruption scenarios, you will need to use a powerful SQL Database Repair application. Such MS SQL Repair software orderly perform database repair and recover all lost database components.