Physical Storage Structures and Types of Available INDEX
Assignment # 5 (Individual)
Submission 29 Dec 11
Objective: To Enhance Analytical Ability and Knowledge * Analyses and Compare the Physical Storage Structures and types of available INDEX of the latest versions of: 1. Oracle 2. SQL Server 3. DB2 4. MySQL 5. Teradata
First of all define comparative framework.
Recommend one product for organizations of around 2000-4000 employees with sound reasoning based on Physical Storage Structures
Introduction to Physical Storage Structures
One characteristic of an RDBMS is the independence of logical data structures such as tables, views, and indexes from physical storage structures. Because physical and logical structures are separate, you can manage physical storage of data without affecting access to logical structures. For example, renaming a database file does not rename the tables stored in it.
The following sections explain the physical database structures of an Oracle database, including datafiles, redo log files, and control files.
Datafiles
Every Oracle database has one or more physical datafiles. The datafiles contain all the database data. The data of logical database structures, such as tables and indexes, is physically stored in the datafiles allocated for a database.
The characteristics of datafiles are: * A datafile can be associated with only one database. * Datafiles can have certain characteristics set to let them automatically extend when the database runs out of space. * One or more datafiles form a logical unit of database storage called a tablespace.
Data in a datafile is read, as needed, during normal database operation and stored in the memory cache of Oracle. For example, assume that a user wants to access some data in a table of a database. If the requested information is not already in the memory cache for the database, then it is read from the appropriate datafiles and stored in memory.
Modified or new data is not necessarily written to a datafile
Submission 29 Dec 11
Objective: To Enhance Analytical Ability and Knowledge * Analyses and Compare the Physical Storage Structures and types of available INDEX of the latest versions of: 1. Oracle 2. SQL Server 3. DB2 4. MySQL 5. Teradata
First of all define comparative framework.
Recommend one product for organizations of around 2000-4000 employees with sound reasoning based on Physical Storage Structures
Introduction to Physical Storage Structures
One characteristic of an RDBMS is the independence of logical data structures such as tables, views, and indexes from physical storage structures. Because physical and logical structures are separate, you can manage physical storage of data without affecting access to logical structures. For example, renaming a database file does not rename the tables stored in it.
The following sections explain the physical database structures of an Oracle database, including datafiles, redo log files, and control files.
Datafiles
Every Oracle database has one or more physical datafiles. The datafiles contain all the database data. The data of logical database structures, such as tables and indexes, is physically stored in the datafiles allocated for a database.
The characteristics of datafiles are: * A datafile can be associated with only one database. * Datafiles can have certain characteristics set to let them automatically extend when the database runs out of space. * One or more datafiles form a logical unit of database storage called a tablespace.
Data in a datafile is read, as needed, during normal database operation and stored in the memory cache of Oracle. For example, assume that a user wants to access some data in a table of a database. If the requested information is not already in the memory cache for the database, then it is read from the appropriate datafiles and stored in memory.
Modified or new data is not necessarily written to a datafile
References: for Teradata http://www.teradata.com/products-and-services/database/ http://teradata.uark.edu/research/wang/indexes.html http://www.teradata.com/products-and-services/database/teradata-13/ http://www.odbms.org/download/illuminate%20Comparison.pdf