Tuesday, November 8, 2011

How to Repair MySQL Database Error 1194

Database administrators use MySQL database tables to store their personal as well as professional data or records. Sometimes, MySQL database throws a below error message:

“ERROR 1194 (HY000): Table 'table_name' is marked as crashed and should be repaired”
where “table_name” is your table table name.

Why this Happen? The first point comes in our mind that why have we got this error message? There are several reasons for this like virus attack, automatic system shutdown, power failure, hardware failure and many more.

Where to Start? To repair MySQL database table corruption, you can follow given below methods.

Method 1: The first method that you can try is Export/Import. To do this follow the below steps:

Export the corrupted or damaged MySQL table.
Delete it.
Import the exported MySQL table.
Repair it throgh “REPAIR_TABLE” syntax

“REPAIR [NO_WRITE_TO_BINLOG | LOCAL] TABLE
    tbl_name [, tbl_name] ...
    [QUICK] [EXTENDED] [USE_FRM]”

Optimize it through “OPTIMIZE_TABLE” syntax.

“OPTIMIZE [NO_WRITE_TO_BINLOG | LOCAL] TABLE
    tbl_name [, tbl_name] ...”

Notification: Method 1 is available for those database administrators that have command line permission.

Method 2: Incase, if you don't have MySQL database command line permission then you can repair corrupt MySQL table through phpMyAdmin. It has repair table option.



Method 3: At last but not least, if above two methods fail to repair corrupt/damaged MySQL database table then you can try any third party MySQL database repair utility.

Thursday, November 3, 2011

Why should backup Your Oracle database

Backup is like second life for any database and it is the most important role of database administrator's job. We can replace corrupt software and hardware with new one but without backup, accessing corrupt oracle database is like nightmare. In some cases you can try any third party oracle database recovery software to recover corrupt/damaged oracle database.

    “If you lose organization's data, may lose your job”  

Schedule to get Backup: you can schedule your routine to get backup of oracle database on daily, weekly and monthly basis. Normally oracle database backup routine depends upon the below factors.

  1. Value of  data: High or Low
  2. Transaction Rate
  3. Number of Users
  4. Database Availability
  5. Many Other

Note: If possible, try to consult your database users before deciding a plan.

Methods for Backing-Up: Oracle database offers four methods for backing-up of an Oracle database.

  • Export/Import
  • Cold or offline backup
  • Hot or online backup
  • RMAN backup

Sometimes backup accomplished by one method is not able to fix the corruption so it is recommended to you to take backup of oracle database by two methods.

Recovery without Backup: Yes, it is possible to recover corrupt oracle database file and its objects without backup. For this, you can try any third party oracle database recovery tool. These tool use advanced scanning algorithm to scan and repair corrupt oracle database file and objects like tables, tablespaces, triggers, views, keys and many more.
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