Consistency : Assures users that the data they are changing or viewing is not changed until the are throw with it.
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Ques 62. Integrity
Assures database data and structures reflects all changes made to them in the correct sequence. Locks ensure data integrity and maximum concurrent access to data. Commit statement releases all locks. Types of locks are given below. Data Locks protects data i.e. Table or Row lock. Dictionary Locks protects the structure of database object i.e. ensures table's structure does not change for the duration of the transaction. Internal Locks & Latches protects the internal database structures. They are automatic. Exclusive Lock allows queries on locked table but no other activity is allowed. Share Lock allows concurrent queries but prohibits updates to the locked tables. Row Share allows concurrent access to the locked table but prohibits for a exclusive table lock. Row Exclusive same as Row Share but prohibits locking in shared mode. Shared Row Exclusive locks the whole table and allows users to look at rows in the table but prohibit others from locking the table in share or updating them. Share Update are synonymous with Row Share.
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Ques 63. Deadlock
Deadlock is a unique situation in a multi user system that causes two or more users to wait indefinitely for a locked resource. First user needs a resource locked by the second user and the second user needs a resource locked by the first user. To avoid dead locks, avoid using exclusive table lock and if using, use it in the same sequence and use Commit frequently to release locks.
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Ques 64. Mutating Table
Mutating Table is a table that is currently being modified by an Insert, Update or Delete statement. Constraining Table is a table that a triggering statement might need to read either directly for a SQL statement or indirectly for a declarative Referential Integrity constraints. Pseudo Columns behaves like a column in a table but are not actually stored in the table. E.g. Currval, Nextval, Rowid, Rownum, Level etc.
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Ques 65. SQL*Loader
SQL*Loader is a product for moving data in external files into tables in an Oracle database. To load data from external files into an Oracle database, two types of input must be provided to SQL*Loader : the data itself and the control file. The control file describes the data to be loaded. It describes the Names and format of the data files, Specifications for loading data and the Data to be loaded (optional). Invoking the loader sqlload username/password controlfilename .