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Big Data Analytics Articles
Page 116 of 135
What are different hashing methods in DBMS?
Hashed file organisation is also called a direct file organisation.In this method, for storing the records a hash function is calculated, which provides the address of the block to store the record. Any type of mathematical function can be used as a hash function. It can be simple or complex.Hash function is applied to columns or attributes to get the block address. The records are stored randomly. So, it is also known as Direct or Random file organization.If the generated hash function is on the column which is considered as key, then the column can be called as hash key ...
Read MoreExplain the importance of centralized databases
Different organizations have struggled with their management information systems and their membership databases. The main struggle here is the lack of centralized information. Too often, assurance and non-profits keep separate databases for membership, events, sales, and other processes. When at all feasible, these databases should be combined into a single, centralized database.Advantages of centralized database over other databasesThe advantages of centralized database over other databases are explained below −Data integrity − In a centralized database the data integrity is maximized and data redundancy is minimized, as the single storing place of all the data also implies that a given set ...
Read MoreWhat is a distributed database?
A distributed database is the one where all the storage devices are not attached to a common CPU (central processing unit). It may be distributed over a network of interconnected computers, or it may be stored in multiple computers located in the same physical location.Distributed Database Management SystemA distributed database management system (DDBMS) manages the database as in if it is stored in the same computer.The DDBMS synchronizes all the data in a periodical manner and in situations when multiple users are accessing the same data and ensures that updation and deletion performed on the data at one location shall ...
Read MoreWhat is the primary index in DBMS?
In the primary index there is a one-to-one relationship between the entries in the index table and records in the main table. Primary index is used on a primary key.Types of Primary IndexPrimary index are of two types, which are as follows −Dense Primary IndexIn a dense primary index an index record appears for every search key value in the main table that means each and every record in the main table has an entry in the index.ExampleGiven below is an example of dense primary index −A pointer stores the address of a record.Non-Dense / Sparse Primary indexAn index record ...
Read MoreDifferentiate between OS and DBMS files and OS and DBMS buffer manager
A Database Management System (DBMS) is a mix of computer software, hardware, and data intended to electronically control information by means of computer preparation.Two sorts of database management systems are DBMS and FMS.In straightforward terms, a File Management System (FMS) is a Database Management System that enables access to single records or tables at once.FMS oblige level records that have no connection to different documents.The FMS was the ancestor for the Database Management System (DBMS), which enables access to various records or tables at once.We have to utilize circle stockpiling for the database, and to exchange pieces of information between ...
Read MoreWhat is the role of file organization modules for typical file system software(DBMS)?
File organization is the way of storing data in the file. It is very useful as it determines ways of accessing it, storing it while maintaining the flexibility of the system.Role of file organizationHence, the roles of file organization are as follows −It provides flexibility.Easy access of data in files.Easy storage.Decrease the complexity of the overall system and files are stored and well maintained.Provide security to data.Saves users time in searching for particular information / data in file as every data is arranged so nicely.MethodsThe methods of file organization are as follows −ContiguousData and files are arranged in contiguous address ...
Read MoreWhat are hashed files and indexed file organization(DBMS)?
Let us begin by understanding the hashed file organisation.Hashed File OrganisationHashed file organisation is also called a direct file organisation.In this method, for storing the records a hash function is calculated, which provides the address of the block to store the record. Any type of mathematical function can be used as a hash function. It can be simple or complex.Hash function is applied to columns or attributes to get the block address. The records are stored randomly. So, it is also known as Direct or Random file organization.If the generated hash function is on the column which is considered as ...
Read MoreWhat is the common source of database failure?
Database failure is a quite common problem of information technology. It can occur even with good database system software. There may be a simple error which can lead to loss of the complete database.Causes of database failureSome of the causes for database failure are as follows −Database file corruptionIf a file in the database is corrupted or damaged, it can lead to the database failure. The file can become corrupt due to the following reasons −Changes in the SQL Server account.Accidental data deletion.File header corruption.Errors in accessing the data.InterruptionWhen the server or computer is not shut down properly or during ...
Read MoreWhat is OLAP? Explain its advantages and disadvantages
OLAP represents online insightful handling and can be characterized as: "Online logical preparation alludes to an assortment of exercises typically performed by End-clients in the online framework."OLAP incorporates choice help, demonstrating, data recovery, impromptu detailing, and imagining a scenario in which investigation. OLAP focuses on choice help needs.ERP framework is a choice help instrument that gives constant data to the board and permits the executives to make convenient choices based on that data that is expected to improve execution and to accomplish determined objectives.Example of OLAPThe case of OLAP can be consolidating deals information by deals channel, item type, and ...
Read MoreWhat are the Database recovery techniques?
Database systems which are similar to some different PC frameworks, are mainly dependent upon disappointments however the information put away in it should be accessible as and when required. At that point, when an information base bombs it should have the offices for quick recuperation. It should likewise have atomicity, For example, either exchanges are finished effectively and submitted (the impact is recorded for all time in the information base) or the exchange ought to have no impact on the data set.There are both programmed and non-programmed ways for both, backing up information and recuperation from any disappointing circumstances. The ...
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