Oracle 9i Database Administration in 10 Minutes
CH1: Understanding the Oracle Environment | CH2: Understanding the Oracle Instance | CH3: Understanding the working of Oracle Instance | CH4: Understanding Oracle Database | CH5: Oracle 9i Software Installation | CH6: Oracle 9i Database Design using DBCA | CH7: Enabling Other Computers to Access Oracle Server | CH8: Oracle Enterprise Manger | CH9: Oracle Backup & Recovery -Simple Technique | CH10: Oracle Performance Tuning
Chapter 4: Understanding Oracle Database
Control File:
Every database has one control file and it basically contains the
information regarding the structure of database. Oracle Instance reads
control file at the time of startup to find out database name, location
of data files and redo log files.
Data Files:
Data files are the files where the actual database’s data resides.
Oracle database can have one or more data files. The size of each data
file is limited to OS (operating system) maximum file size. But the size
of the Oracle Database can be whatever you like. There is no limit on
the maximum size of the database. If you are running out of space you
can always add more data files to the database.
Figure 10: Physical Architecture: Oracle Database
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Redo Log Files & Archived Redo Log Files:
Redo Log files are the files that maintains the changes happening in
data. Every Oracle Database has set of two or more redo log files. Each
set is called redo log file group. Redo log files gets utilized in a
circular fashion i.e. when Oracle Instance finishes writing the last
redo log file then it starts overwriting the first one.
The way we can protect overwriting of Redo Log files is to run the
Oracle Instance in Archive Log Mode. If Oracle is running in this mode
then redo log files will get archived to the destination you specify in
the parameter file before getting overwritten.
Parameter File (PFILE):
Parameter file contains the name of the database, location of control
file, memory structure of Oracle Instance and certain other necessary
Oracle system configuration parameters. PFILE is read by Oracle Instance
while starting up the database or even before that i.e. when the
Instance creates itself.
Chapter 4: Understanding Oracle Database
CH1: Understanding the Oracle Environment | CH2: Understanding the Oracle Instance | CH3: Understanding the working of Oracle Instance | CH4: Understanding Oracle Database | CH5: Oracle 9i Software Installation | CH6: Oracle 9i Database Design using DBCA | CH7: Enabling Other Computers to Access Oracle Server | CH8: Oracle Enterprise Manger | CH9: Oracle Backup & Recovery -Simple Technique | CH10: Oracle Performance Tuning
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