The Primary function of the redo log is to record all changes made to data.
Latest Answer: Oracle maintains logs of all transactions against the databse. These transactions are recorded in files called Online Redo log files.These logs are used to recover the database's transaction in their proper order in the evnt of database crash. The redo ...
The Information in a redo log file is used only to recover the database from a system or media failure prevents database data from being written to a database's data files.
Latest Answer: Oracle maintains logs of all transactions against the databse. These transactions are recorded in files called Online Redo log files.These logs are used to recover the database's transaction in their proper order in the evnt of database crash. The redo ...
A Control file records the physical structure of the database. It contains the following information.Database NameNames and locations of a database's files and redolog files.Time stamp of database
Latest Answer: The controlfile contains :1. Name and Location of Datafiles, Redo Logfiles.2. Timestamp of Database Creation.3. Current log sequence number is recorded when log switches are occur.4. Checkpoint information is recorded as checkpoints are made.5. Database ...
When an instance of an ORACLE database is started, its control file is used to identify the database and redo log files that must be opened for database operation to proceed. It is also used in database
Latest Answer: Uses of a Controlfile:1.It is used to identify the names and locations of datafiles,redologfiles.2.Redo History is recorded during log switches.3.Checkpoint information is recorded at ckpts are made.4.Timestamp of database creation.5.Database information ...
The data dictionary of an ORACLE database is a set of tables and views that are used as a read-only reference about the database.It stores information about both the logical and physical structure of the
Latest Answer: Data Dictionary is a read-only set of tables that provides information about the database. in order to avoid the I/O cost, these data dictionary views are used ...
An integrity constraint is a declarative way to define a business rule for a column of a table.
Latest Answer: Special requirements for table data:1) allow NULL value2) uniqueness of value3) primary key4) foreign key5) special value size/text/length etc requirementsAll information is stored in Data Dictionary. ...
Can an Integrity Constraint be enforced on a table if some existing table data does not satisfy the constraint ?
No.
NOT NULL Constraint - Disallows Nulls in a table's column.UNIQUE Constraint - Disallows duplicate values in a column or set of columns.PRIMARY KEY Constraint - Disallows duplicate values and Nulls
A column defined as UNIQUE can contain Nulls while a column defined as PRIMARY KEY can't contain Nulls.
Latest Answer: A table can have any number unique keys but a single primary key ...
A rule defined on a column (or set of columns) in one table that allows the insert or update of a row only if the value for the column or set of columns (the dependent value) matches a value in a column
Latest Answer: Referential integrity is a relationship between two tables, one being the 'parent' and the other being the 'child'. The 'child' table references values in the 'parent' table's primary key to ensure all data between ...
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