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What is the difference between database instance and relation schema?
Database Instance The term instance is typically used to describe a complete database environment, including the RDBMS software, table structure, stored procedures and other functionality. It is most commonly used when administrators describe multiple instances of the same database.Also Known As: environment Examples: An organization with an employees database might have three different instances: production (used to contain live data), pre-production (used to test new functionality prior to release into production) and development (used by database developers to create new functionality). RELATION SCHEMA A relation schema can be thought of as the basic information describing a table or relation. This includes a set of column names, the data types associated with each column, and the name associated with the entire table. For example, a relation schema for the relation called Students could be expressed using the following representation: Students(sid: string, name: string, login: string, age: integer, gpa: real) There are five fields or columns, with names and types as shown above.
Difference between alter and update commands in sql?
Update and Alter are two SQL (Structured Query Language) commands used for modifying databases. Update statement is used to update existing records in a database. Update is a Data Manipulation Language (DML) statement. Alter SQL command is used to modify, delete or add a column to an existing table in a database. Alter is a Data Definition Language (DDL) statement.Commands that are used to define the structure of a database (database schema) are called DDL statements.
What is a conjuctive adverb?
Used to express relationships between independent clauses.
What is a relational database query and Explain with an example?
A relational database matches data by using common characteristics found within the data set. The resulting groups of data are organized and are much easier for many people to understand.For example, a data set containing all the real-estate transactions in a town can be grouped by the year each transaction occurred, the sale price, a buyer's last name and so on. Such a grouping uses the relational model (a technical term for this is schema). Hence, such a database is called a "relational database."The software used to do this grouping is called a relational database management system (RDBMS). The term "relational database" often refers to this type of software.Relational databases are currently the predominant choice in storing data like financial records, medical records, personal information and manufacturing and logistical data.
Which can be used to represent a many to many relation with abstract data types?
tree
Differentiate logical and physical database?
After all business requirements have been gathered for a proposed database, they must be modeled. Models are created to visually represent the proposed database so that business requirements can easily be associated with database objects to ensure that all requirements have been completely and accurately gathered. Different types of diagrams are typically produced to illustrate the business processes, rules, entities, and organizational units that have been identified. These diagrams often include entity relationship diagrams, process flow diagrams, and server model diagrams. An entity relationship diagram (ERD) represents the entities, or groups of information, and their relationships maintained for a business. Process flow diagrams represent business processes and the flow of data between different processes and entities that have been defined. Server model diagrams represent a detailed picture of the database as being transformed from the business model into a relational database with tables, columns, and constraints. Basically, data modeling serves as a link between business needs and system requirements. Two types of data modeling are as follows: * Logical modeling * Physical modeling If you are going to be working with databases, then it is important to understand the difference between logical and physical modeling, and how they relate to one another. Logical and physical modeling are described in more detail in the following subsections. Logical modeling deals with gathering business requirements and converting those requirements into a model. The logical model revolves around the needs of the business, not the database, although the needs of the business are used to establish the needs of the database. Logical modeling involves gathering information about business processes, business entities (categories of data), and organizational units. After this information is gathered, diagrams and reports are produced including entity relationship diagrams, business process diagrams, and eventually process flow diagrams. The diagrams produced should show the processes and data that exists, as well as the relationships between business processes and data. Logical modeling should accurately render a visual representation of the activities and data relevant to a particular business. The diagrams and documentation generated during logical modeling is used to determine whether the requirements of the business have been completely gathered. Management, developers, and end users alike review these diagrams and documentation to determine if more work is required before physical modeling commences. Typical deliverables of logical modeling include * Entity relationship diagrams An Entity Relationship Diagram is also referred to as an analysis ERD. The point of the initial ERD is to provide the development team with a picture of the different categories of data for the business, as well as how these categories of data are related to one another. * Business process diagrams The process model illustrates all the parent and child processes that are performed by individuals within a company. The process model gives the development team an idea of how data moves within the organization. Because process models illustrate the activities of individuals in the company, the process model can be used to determine how a database application interface is design. * User feedback documentation Physical modeling involves the actual design of a database according to the requirements that were established during logical modeling. Logical modeling mainly involves gathering the requirements of the business, with the latter part of logical modeling directed toward the goals and requirements of the database. Physical modeling deals with the conversion of the logical, or business model, into a relational database model. When physical modeling occurs, objects are being defined at the schema level. A schema is a group of related objects in a database. A database design effort is normally associated with one schema. During physical modeling, objects such as tables and columns are created based on entities and attributes that were defined during logical modeling. Constraints are also defined, including primary keys, foreign keys, other unique keys, and check constraints. Views can be created from database tables to summarize data or to simply provide the user with another perspective of certain data. Other objects such as indexes and snapshots can also be defined during physical modeling. Physical modeling is when all the pieces come together to complete the process of defining a database for a business. Physical modeling is database software specific, meaning that the objects defined during physical modeling can vary depending on the relational database software being used. For example, most relational database systems have variations with the way data types are represented and the way data is stored, although basic data types are conceptually the same among different implementations. Additionally, some database systems have objects that are not available in other database systems. Typical deliverables of physical modeling include the following: * Server model diagrams The server model diagram shows tables, columns, and relationships within a database. * User feedback documentation Database design documentation Understanding the difference between logical and physical modeling will help you build better organized and more effective database systems.
what is data modeling?
A data model is a conceptual frame work that outlines how data is structured, organized, and stored with in a database or information system. It defines relationships between different data types and specifies rules and constraints for data access and manipulation. Visual representations such as entity-relationship diagrams or UML diagrams, are often used to illustrate data model structures.
What are some types of database?
Some commonly used database softwares are:OracleSQL ServerIBM DB2SybaseMS Access etc
What are data types in a database?
They are types of data used in a field for example Text, Currencey ect
Design notation modeling languages?
Design notation modeling languages are graphical languages used to represent. Communicate design concepts, structures, and relationships. These languages provide a standardized way to visually express design ideas. Facilitate effective communication among designers, stakeholders, and developers. Some popular design notation modeling languages include: 1. UML (Unified Modeling Language): Widely used in software engineering. UML provides a set of standardized diagrams to represent various aspects of a system. Such as class diagrams, use case diagrams, sequence diagrams, and more. 2. BPMN (Business Process Model and Notation): Used for modeling business processes. BPMN allows the visual representation of activities, events, gateways, and flows. To describe the flow of work within an organization. 3. ERD (Entity-Relationship Diagram): Commonly used in database design. ERD represents the relationships between entities and attributes in a database system. Helping to define the structure and organization of data. 4. SysML (Systems Modeling Language): A language based on UML, SysML extends its capabilities to capture. model complex systems, including hardware, software, and their interactions. 5. ArchiMate: Primarily used for enterprise architecture modeling. ArchiMate provides a comprehensive framework for describing. And visualizing the components, relationships, and dependencies of an organization's architecture. These modeling languages serve as powerful tools to document. Analyze, and communicate designs across various domains and industries.
What are the Different types of relationship in a database?
There are mainly three types of relationships in database . These are One to One , One to Many , Many to Many. One to one relationship can be seen as relationship between husband and wife , one to many relationship can be seen as a relationship between a college and students.
What is the importance of data modeling?
A data model is a (relatively) simple abstraction of a complex real-world data environment. Database designers use data models to communicate with applications programmers and end users. The basic data-modeling components are entities, attributes, relationships, and constraints. Business rules are used to identify and define the basic modeling components within a specific real-world environment.
What is the select element?
To retrieve or modify data in the database query are used. There are four types of commands in SQL. Select command is data retrieval language command and is used to retrieve data from a database.In database there Four types of languages which contains various commands. Select command is the only command that is used for retrieval of data.
What is network model in DBMS?
network model is a collection data in which records are physically linked through linked lists .A DBMS is said to be a Network DBMS if the relationships among data in the database are of type many-to-many. The relationships among many-to-many appears in the form of a network. Thus the structure of a network database is extremely complicated because of these many-to-many relationships in which one record can be used as a key of the entire database. A network database is structured in the form of a graph that is also a data structure .
Name types of applications used in mis?
An application in a management information system can be a database. The database stores information the business uses to make decisions.
What is numbers used for in terms of database?
For creating a table we need to mention the field names and data types . Numbers is a datatype in database for storing integers in a field .
Seven types of these are contained in an Access database and are used to enter or enhance and use the data within the database?
You would like to analyze data contained in an on-premises Access database. How will you do this with Power BI service?
