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Offset-Fetch is feature in MS SQL Server. It helps to retrieve subset of rows from result set. It consists of two components: OFFSET and FETCH. The OFFSET clause specifies the number of rows to skip from the beginning of the result set. FETCH clause determines the number of rows to retrieve. Syntax SELECT column1, column2, ... FROM table ORDER BY column OFFSET {integer_value} {ROWS | ROWS ONLY} FETCH {FIRST | NEXT} {integer_value} {ROWS | ROWS ONLY} ONLY; Explanation of Syntax SELECT column1, column2, ...: Specifies the columns to be selected from the table. FROM table Specifies the table from ... Read More
OLAP (Online Analytical Processing) is data processing technique. It is used to query and analyze data. It analyze data in real time from multiple sources. In 1993, EF Codd introduced 12 rules for the relational database model for OLAP systems. These rules are known as "Codd’s rules". These rules serve as a guideline for the design and development of OLAP systems. In this article, we will explore these 12 rules developed by Codd. Codd’s rules These are 12 rules for OLAP systems, as proposed by E.F. Codd − Multidimensional Conceptual View OLAP system should provide multidimensional conceptual view of ... Read More
Online Analytical Processing Server (OLAP) is used to enable users to perform analysis on information retrieved from multiple database systems concurrently. It operates on a multidimensional data model. Users can write query data across multiple dimensions, such as location, time, and categories (e.g., Hyderabad-> 2017 -> Sales data). In OLAP, databases are organized into one or more cubes. These cubes are known as Hyper-cubes and represent a multi-dimensional array of data. Each cell within the array corresponds to specific combination of dimension values. The dimensions define the characteristics or attributes. Data can be sliced and diced for analysis by attributes. ... Read More
On-Line Transaction Processing (OLTP) System is a type of computer system that helps manage transaction-related tasks. These systems are made to quickly handle transactions and queries on the internet. For instance, supermarket's POS (point of sale) system is an example of an OLTP system. Almost every industry nowadays uses OLTP systems to keep track of their transactional data. OLTP systems mainly focus on entering, storing, and retrieving data, which includes daily operations like purchasing, manufacturing, payroll, accounting, etc. Many users use these systems for short transactions. They support simple database queries, which makes it easier for users to get ... Read More
Retrieval and Update Operations When we work with files, we usually do two types of operations: retrieval and update. Retrieval operations help us find specific records in the file and look at their data. Update operations change the file by adding, removing, or modifying records. Selection Conditions To do either operation, we may need to specify a condition that the records must meet. For example, we might want to retrieve all the records where the salary is greater than or equal to $30, 000. This is called a selection condition. Selection conditions can be simple or complex. A simple condition ... Read More
Cassandra is a distributed NoSQL database system. It offers high scalability, availability, and fault-tolerance. It uses a decentralized architecture, where data is distributed across multiple nodes, and provides several operations to manipulate data. In this article, we will discuss operations on tables in Cassandra. Creating Tables The first operation in Cassandra is to create a table. A table is defined by set of columns. Each column has name, data type, and an optional value. To create a table, you need to specify the keyspace. It is namespace that defines the replication strategy, and the table name. You also need to ... Read More
In Python, classes are like blueprints for creating objects. Once you define a class, you can create objects (also called instances) based on that class. Here are four ways to create class objects in Python: Creating a Class and an Instance Example In this example, we define a class called `MyClass` using the `class` keyword. We then create an instance of the class called `obj` using parentheses `()` after the class name. This creates an empty object that is an instance of the class. class MyClass: pass obj = MyClass() print(obj) Output ... Read More
Oracle Label-Based Security (OLS) is a feature of the Oracle Database that provides fine-grained access control over sensitive data based on security labels. This feature enables organizations to enforce access control policies based on the sensitivity of the data rather than the traditional approach of user roles and privileges. In this article, we will discuss how Oracle Label-Based Security works and its benefits. Oracle Label-Based Security Oracle Label-Based Security works by assigning a security label to each row of data in a table. The label identifies the sensitivity level of the data, such as confidential, secret, or top secret. Each ... Read More
Files of Mixed Records In DBMS, file organizations are designed to handle records of a single type. However, in most real-world applications, multiple types of entities are interconnected in various ways. To represent relationships among records in different files, fields are connected. For example, a STUDENT record may have a connecting field Major_dept, whose value gives the name of the DEPARTMENT in which the student is majoring. The Major_dept field refers to a DEPARTMENT entity, which should be represented by a record of its own in the DEPARTMENT file. Retrieving field values from two related records requires retrieving one of ... Read More
Introduction Neurobiology or Neuroscience is the scientific study of the nervous system (the brain, spinal cord, and peripheral nervous system), its functions and disorders. It is a multidisciplinary science that combines physiology, anatomy, molecular biology, developmental biology, cytology, psychology, physics, computer science, chemistry, medicine, statistics, and mathematical modeling to understand the fundamental and emergent properties of neurons, glia, and neural circuits. The scope of neuroscience has broadened over time to include different approaches used to study the nervous system at different scales. The techniques used by neuroscientists have expanded enormously, from molecular and cellular studies of individual neurons to imaging ... Read More