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What are hierarchical databases and give me some examples?
A hierarchical database model is a data model in which the data is organized into a tree-like structure. The structure allows representing information using parent/child relationships: each parent can have many children, but each child has only one parent.
Difference between hierarchical and Network data module?
The hierarchical data model organizes data in a tree-like structure with a single parent for each child record. On the other hand, the network data model allows for multiple parent-child relationships, creating a more flexible and complex network of interconnected records. In the hierarchical model, relationships are one-to-many, while in the network model, relationships can be many-to-many.
Difference between network model and hierarchical model and relational model?
The relational model is a model in which data is isolated by object and foreign keys to those objects which is organized in tables with multiple columns or attributes. The hierarchical model is a model in which the data is organized in a tree structure that allows repeating information using parent/child relationships.
How is data organized in hierarchical data model?
The hierarchical model is a restricted type of network model. Again, data is represented as collections of records and relationships are represented by sets. However, the hierarchical model allows a node to have only one parent. A hierarchical model can be represented as a tree graph, with records appearing as nodes (also called segments) and sets as edges.
2 Explain why navigation is simple in Relational Data Model than in Hierarchical?
Navigation in the Relational Data Model is simpler than in the Hierarchical Data Model due to the relational structure of tables linked by common keys. In the Relational Data Model, data is organized into tables with rows and columns, allowing for easy querying and retrieval of information using SQL queries. On the other hand, in the Hierarchical Data Model, data is organized in a tree-like structure with parent-child relationships, making navigation more complex and requiring traversal of multiple levels to access specific data points.
What are all the major applications of network data model and hierarchical data model?
The hierarchical data model organizes data in a tree structure. There is a hierarchy of parent and child data segments. This structure implies that a record can have repeating information, generally in the child data segments. Data in a series of records, which have a set of field values attached to it. It collects all the instances of a specific record together as a record type. These record types are the equivalent of tables in the relational model, and with the individual records being the equivalent of rows. To create links between these record types, the hierarchical model uses Parent Child Relationships. These are a 1:N mapping between record types. This is done by using trees, like set theory used in the relational model, "borrowed" from maths. For example, an organization might store information about an employee, such as name, employee number, department, salary. The organization might also store information about an employee's children, such as name and date of birth. The employee and children data forms a hierarchy, where the employee data represents the parent segment and the children data represents the child segment. If an employee has three children, then there would be three child segments associated with one employee segment. In a hierarchical database the parent-child relationship is one to many. This restricts a child segment to having only one parent segment. Hierarchical DBMSs were popular from the late 1960s, with the introduction of IBM's Information Management System (IMS) DBMS, through the 1970s.---- The popularity of the network data model coincided with the popularity of the hierarchical data model. Some data were more naturally modeled with more than one parent per child. So, the network model permitted the modeling of many-to-many relationships in data. In 1971, the Conference on Data Systems Languages (CODASYL) formally defined the network model. The basic data modeling construct in the network model is the set construct. A set consists of an owner record type, a set name, and a member record type. A member record type can have that role in more than one set, hence the multiparent concept is supported. An owner record type can also be a member or owner in another set. The data model is a simple network, and link and intersection record types (called junction records by IDMS) may exist, as well as sets between them . Thus, the complete network of relationships is represented by several pairwise sets; in each set some (one) record type is owner (at the tail of the network arrow) and one or more record types are members (at the head of the relationship arrow). Usually, a set defines a 1:M relationship, although 1:1 is permitted. The CODASYL network model is based on mathematical set theory.
What are the features of a database?
A hierarchical database organizes data in a "tree like" structure. The "main" data point (known as the parent) may have many "sub" data points (known as children), but each child only has one parent.
What are the different data model in DBMS?
"A data model is a collection of concepts that can be used to describe the structure of a database." Data models can be broadly distinguished into 3 main categories- 1)high-level or conceptual data models (based on entities & relationships) - It provides concepts that are close to the way many users perceive data. 2)lowlevel or physical data models - It provides concepts that describe the details of how data is stored in the computer.These concepts are meant for computer specialist, not for typical end users. 3)representational or implementation data models (record-based,object- 0riented) - It provide concepts that can be understood by end users. These hide some details of data storage but can be implemented on a computer system directly.
What are the features of a hierarchical database?
A hierarchical database organizes data in a "tree like" structure. The "main" data point (known as the parent) may have many "sub" data points (known as children), but each child only has one parent.
How an abusive parent affect a child?
Data shows that a child who is abused will in turn become an abuser later in life. The life of an abused child is affected his/her entire life.
- How does the hierarchical data model address the problem of data redundancy?
The hierarchical model divides the data into parents and children with the system working on the principle that each child can have only one parent but each parent can have an infinate number of children - thus supporting one-to-manyrelationships.This means that data redundency is reduced as a relationship can be established between entities e.g. in a school system each course would be a parent, with each student being the child, and each grade being the child of the student.This would allow you to createa one-to-many relationship between the students on each course and the grades for each pupil.However this system is not ideal for this scenario, as if a student was enrolled on more than one course their details would have to be duplicated for each course.To deal with this many-to-many relationship you would need to create a relational database, creating a studentcourses entity with a one to many relationship occurring between both it and a student entity and it and a courses entity
What is hierarchical structure in dbms?
In hierarchical database structure, data elements are linked together as an inverted tree structure. there's a root data element, below the root ,there are subordinate elements, each of which has its own subordinate elements and so on. It can have multiple levels. Data elements have parent-child relationship. A parent data element can have more than one subordinate elements, but a child can be connected with only one parent. Its limitation is it cannot provide flexibility in data access. because every data element can be accessed through a definite path from the root data element. All the relationships between data elements should map properly when tree structure is first designed.this database model is used in several database applications because data elements of several applications can be organized as a hierarchical tree structure.
