Super Key is an attribute (or a set of attributes) that uniquely identify a tuple i.e. an entity in entity set.It is a superset of Candidate Key, since Candidate Keys are selected from super key.ExampleLet us see an example −Student_IDStudent_EnrollStudent_NameStudent_EmailS024545Daveddd@gmail.comS344541Jackjjj@gmail.comS224555Markmmm@gmail.comThe following are the super keys for the above table −{Student_ID}{Student_Enroll}{Student_Email}{Student_ID, ... Read More

To trim a string in jQuery, use the trim() method. It removes the spaces from starting and end of the string.The sample string I am using has spaces −var myStr = "  Hello World    ";Use the trim() method,  jQuery.trim(myStr);The following is an example to trim a string in jQuery ... Read More

A Foreign Key creates a link between tables. It references the primary key in another table and links it.For example, the DeptID in the Employee table is a foreign key −EmpIDEmpNameEmpAgeDeptIDDeptIDDeptNameDeptZoneThe DeptID in the Department table is a Primary Key in the Department Table.The DeptID in the Employee table is a Foreign ... Read More

Each table has only a single primary key. Each relation may have one or more candidate key. One of these candidate key is called Primary Key. Each candidate key qualifies for Primary Key. Therefore candidates for Primary Key is called Candidate Key.Candidate key can be a single column or combination ... Read More

Identifying entity relationships in DBMS is used to identify a relationship between strong and weak entity.Before beginning, let us take an example of Professor entity, which is our Strong Entity, with Professor_ID as a Primary Key −Professor_IDProfessor_NameProfessor_CityProfessor_SalaryThe weak entity is Professor_Dependents entity:NameDOBRelationNow, let us continue, Weak EntityWeak Entity is dependent on Strong Entity ... Read More

Managing data was the key and was essential. Therefore, data model originated to solve the file system issues. Here are the Data Models in DBMS −Hierarchical ModelIn Hierarchical Model, a hierarchical relation is formed by collection of relations and forms a tree-like structure.The relationship can be defined in the form ... Read More

The jQuery filter() method will return elements matching a specific criteria. The following are the parameters for the jQuery.filter() methods, S.NoParameterDescription1criteriaThis specifies a selector expression, or one or more elements. These elements are returned from a group of selected elements.2function(index)This specifies a function to run for every element. This is ... Read More

To find anchor tag in div, use a selector and the addClass() method adds a class using jQuery.You can try to run the following code to learn how to find anchor tag in div and add class:Live Demo                     ... Read More

With jQuery, it’s easy to get selected text from a drop-down list with :selected. This is done using the select id. You can try to run the following code to learn how to get selected text from a drop-down list using jQuery −ExampleLive Demo           jQuery ... Read More

Using jQuery, you can detect if a specific element in the page is hidden or visible with is(:visible). You can try to run the following code to learn how to check if an element is hidden in jQuery or not −ExampleLive Demo           jQuery Selector   ... Read More