N-ary Relationship in Database

Amit Diwan
Updated on 20-Jun-2020 09:52:14

9K+ Views

A relationship is an important part of any Entity relationship diagram as it shows the relation between two different entities. In an n - ary relationship, the n shows the number of entities in the relationship. It can be anything but the most popular relationships are unary, binary and ternary where the number of entities respectively are one, two and three.More information about Unary, Binary and Ternary relationships is as follows −Unary RelationshipWhen there is a relationship between two entities of the same type, it is known as a unary or recursive relationship. This means that the relationship is between ... Read More

Operating system time slicing in round robin scheduling

Arnab Chakraborty
Updated on 20-Jun-2020 09:50:34

191 Views

process Burst time A 4 B 1 C 8 D 1time slice=10 unitA B C D A C C C 0 2 3 5 6 8 10 12 14So A will complete 8 cycles.

Functions in Oracle DBMS

Amit Diwan
Updated on 20-Jun-2020 09:50:11

6K+ Views

The different types of functions in Oracle are −Oracle String FunctionsOracle Numeric FunctionsOracle Date FunctionsMore details about these functions are given as follows −Oracle String FunctionsThe following are the Oracle String Functions −ASCII(str)This function returns the ASCII or numeric value of the first word in the string str provided. If it is an empty string, it returns 0. For example:SQL> SELECT ASCII('Apple'); +---------------------------------------------------------+ | ASCII('Apple') | +---------------------------------------------------------+ | 65 | +---------------------------------------------------------+ 1 row in set (0.00 sec)This returns the ASCII value of A i.e. 65 as it is the first character in the string.CONCAT(str1, str2…..strn)This function returns the string that ... Read More

Distributed Database Management System

Kristi Castro
Updated on 20-Jun-2020 09:47:11

2K+ Views

In a distributed database management system, the database is not stored at a single location. Rather, it may be stored in multiple computers at the same place or geographically spread far away. Despite all this, the distributed database appears as a single database to the user. A diagram to better explain this is as follows:As seen in the figure, the components of the distributed database can be in multiple locations such as India, Canada, Australia, etc. However, this is transparent to the user i.e the database appears as a single entity.Types of Distributed Database Management SystemThe following are the types ... Read More

C# String Methods

Samual Sam
Updated on 20-Jun-2020 09:46:54

538 Views

The String class has many methods that help you in working with the string objects. The following table has some of the most commonly used methods −Sr.NoMethod & Description1public static int Compare(string strA, string strB)Compares two specified string objects and returns an integer that indicates their relative position in the sort order.2public static int Compare(string strA, string strB, bool ignoreCase )Compares two specified string objects and returns an integer that indicates their relative position in the sort order. However, it ignores case if the Boolean parameter is true.3public static string Concat(string str0, string str1)Concatenates two string objects.4public static string Concat(string ... Read More

Class in C#

karthikeya Boyini
Updated on 20-Jun-2020 09:45:26

115 Views

Blueprint for a data type is what you can call a class in C#. Objects are instances of a class. The methods and variables that constitute a class are called members of the class.ExampleThe following is the general form of a class in C# − class class_name {    // member variables     variable1;     variable2;    ...     variableN;    // member methods     method1(parameter_list) {       // method body    }     method2(parameter_list) {       // method body    }    ...     methodN(parameter_list) {       ... Read More

Concurrency Control Using Locks in DBMS

David Meador
Updated on 20-Jun-2020 09:43:06

11K+ Views

Locks are an integral part to maintain concurrency control in DBMS. A transaction in any system implementing lock based concurrency control cannot read or write a statement until it has obtained the required locks.There are two types of locks in Lock based protocols. These are:Binary Locks - These can only be in one of two states, locked or unlocked.Shared/Exclusive Locks - Shared locks are acquired when only read operation is to be performed. Shared locks can be shared between multiple transactions as there is no data being altered. Exclusive locks are used when write operation is performed. Only the transaction holding the ... Read More

What kind of settings can we do to a text file by query while exporting the values from MySQL table into a text file?

vanithasree
Updated on 20-Jun-2020 09:26:54

63 Views

While exporting the data from MySQL table to a text file we can use ‘FIELDS TERMINATED BY’, ‘ENCLOSED BY’, ‘LINES TERMINATED BY’ and other options too to put the values of fields in different settings of the text file. It can be illustrated with the help of the following example −ExampleSuppose we are having following data from table ‘Student_info’ −mysql> Select * from Student_info; +------+---------+------------+------------+ | id   | Name    | Address    | Subject    | +------+---------+------------+------------+ | 101  | YashPal | Amritsar   | History    | | 105  | Gaurav  | Chandigarh | Literature | | ... Read More

Classes vs Structures in C#

Samual Sam
Updated on 20-Jun-2020 09:26:22

564 Views

In C#, a structure is a value type data type. It helps you to make a single variable hold related data of various data types. The struct keyword is used for creating a structure.When you define a class, you define a blueprint for a data type.The following are the differences between classes and structures in C# −Classes are reference types and structs are value typesUnlike classes, structures cannot inherit other structures or classes.Structures cannot be used as a base for other structures or classes.When you create a struct object using the New operator, it gets created and the appropriate constructor ... Read More

Collections in C#

karthikeya Boyini
Updated on 20-Jun-2020 09:26:03

185 Views

Collection classes are specialized classes for data storage and retrieval. These classes provide support for stacks, queues, lists, and hash tables. Most collection classes implement the same interfaces.The following are the collection classes in C# −ArrayListThe ArrayList class represents ordered collection of an object that can be indexed individually.HashtableHashtable uses a key to access the elements in the collection.SortedListIt uses a key as well as an index to access the items in a list.BitArrayIt represents an array of the binary representation using the values 1 and 0.StackIt represents a last-in, first out collection of object.QueueIt represents a first-in, first out ... Read More

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