Database Programming

Data independence is a form of database management that keeps data separated from all programs that make use of the data. As a cornerstone for the idea of a DBMS or database management system, data independence ensures that the data cannot be redefined or reorganized by any of the programs that make use of the data. In this manner, the dataremains accessible, but is also stable and cannot be corrupted by the applications using it.

You can link them using Keys. You have different kinds of keys like Foreign key, super key etc.

Foreign key - a foreign key (FK) is a field or group of fields in a database record that points to a key field or group of fields forming a key of another database record in some (usually different) table. Usually a foreign key in one table refers to the primary key (PK) of another table. This way references can be made to link information together and it is an essential part of database normalization

Superkey - A superkey is defined in the relational model as a set of attributes of a relation variable (relvar) for which it holds that in all relations assigned to that variable there are no two distinct tuples (rows) that have the same values for the attributes in this set. Equivalently a superkey can also be defined as a set of attributes of a relvar upon which all attributes of the relvar are functionally dependent.

* The UNION operator combines the output of two query expressions into a single result set. Query expressions are executed independently, and their output is combined into a single result table. * The EXCEPT operator evaluates the output of two query expressions and returns the difference between the results. The result set contains all rows returned from the first query expression except those rows that are also returned from the second query expression. * The INTERSECT operator evaluates the output of two query expressions and returns only the rows common to each.

Strengths: The theory helps understand the influence of media on individuals and society, highlighting the power dynamics at play. It emphasizes the importance of media in shaping opinions and behaviors.

Weaknesses: The theory oversimplifies complex relationships between media and audiences, neglecting individual agency and other factors that influence media consumption. It can be criticized for being deterministic and not accounting for varying levels of media influence.

MIS (Management Information Systems) refers to the use of information systems to aid in managerial decision-making. It involves the collection, processing, and analysis of data to generate meaningful information for management.

Data processing, on the other hand, is a broader term that refers to the manipulation and transformation of data to produce useful information. It includes activities such as data entry, validation, sorting, summarizing, and generating reports. MIS is a specific application of data processing within a managerial context.

A criteria that searches for fields that are not empty is called a "not null" criteria. This criteria is used to filter out records where a specific field does not have a null or empty value.

Object-oriented database management systems (OODBMS) store data in a way that aligns with object-oriented programming concepts, allowing for complex data structures and relationships to be easily represented. On the other hand, object-relational database management systems (ORDBMS) combine relational database capabilities with object-oriented features, enabling users to work with both traditional relational data and more complex data types. ORDBMS often use SQL as the query language, whereas OODBMS may use object query languages.

System theory provides a holistic perspective, allowing for the examination of complex interactions among components within a system. It helps in understanding the interdependencies and relationships within systems, facilitating effective problem-solving and decision-making. Additionally, system theory emphasizes feedback mechanisms, enabling systems to adapt and evolve in dynamic environments.

SQL is used to communicate with and manage databases. You can use it to retrieve, insert, update, and delete data from databases. It is also used for creating tables, views, functions, and stored procedures.

1. Data Marts design(Modelling) -- contains dimension and fact tables

2. ETL (extract transform load) -- how to load data from multiple db to datamart with transformation logic. e.g. using Informatica, Microsoft SSIS, Data Stage

3. Business Intelligence - Reporting e.g. BO,Cognos etc

A database contains structured data organized in tables to store and manage information efficiently. It typically includes fields for different data types, rows for individual records, and relationships between tables to establish data integrity. The data can be retrieved, manipulated, and queried using database management systems.

Maintaining data integrity is important to ensure that data is accurate, consistent, and reliable. It helps in making informed decisions, building trust with stakeholders, and complying with regulations. Without data integrity, there is a risk of making errors, misleading analysis, and damaging the reputation of the organization.

A primary key is a special case of unique keys which doesnt accept duplicates. The difference between unique keys is that "NOT NULL" constraint is not automatically enforced, while for primary keys it is mandatory

Unique keys and primary keys can be referenced by foreign keys

SQL LOADER is an Oracle utility used to load data into table given a datafile which has the records that need to be loaded. SQL*Loader takes data file, as well as a control file, to insert data into the table. When a Control file is executed, it can create Three (3) files called a log file, bad file or reject file, discard file. * Log file tells you the state of the tables and indexes and the number of logical records already read from the input datafile. This information can be used to resume the load where it left off. * Bad file or reject file gives you the records that were rejected because of formatting errors or because they caused Oracle errors. * Discard filespecifies the records that do not meet any of the loading criteria like when any of the WHEN clauses specified in the control file. These records differ from rejected records.

SQL allows for easy access and retrieval of large amounts of data, provides a standardized language for interacting with databases, and offers powerful tools for data manipulation and analysis. Additionally, SQL supports data integrity and security features to ensure reliable and secure data management.

Conceptual(high-level, semantic ) data models:

Provide concepts that are close to the way many user perceive data.

Physical(low -level, internal) data models:

Provide concepts that describe details of how data is stored in the computer.

Implementation(representational) data models:

Provide concepts that fall between the above two, used by many commercial DBMS Implementation.

Distributed systems refer to a network of independent computers that work together to achieve a common goal, while distributed database systems specifically involve databases that are spread across multiple locations. Distributed database systems focus on storing and managing data across various nodes in a network, whereas distributed systems are more general and encompass a broader range of functionalities beyond data management.

"Let's go to the movies at 10 pm." - This sentence segment is correctly punctuated.

A field and a table are both components of a database system. A field represents a single piece of data within a record, while a table is a collection of related records organized in rows and columns. Tables consist of fields that define the structure of the data stored within them.

The first database management system (DBMS), known as the Integrated Data Store, was developed by Charles Bachman in 1963. This marked the beginning of modern database systems.

The SQL statement used to delete data from a database is DELETE FROM table_name WHERE condition;. This statement deletes rows from the specified table based on the condition provided. Make sure to use caution when using DELETE statements as they permanently remove data from the database.

A record in a database management system (DBMS) is a basic unit of data storage containing information about a single entity or item. It is composed of fields that represent specific attributes or characteristics of the entity being stored. Records are organized within database tables and can be accessed, updated, or deleted using SQL queries.

Database is an organized collection of facts and information. Most managers ans executives consider a database one OS the mos valubale part of a computer-based information system because contains facts and information on customers, employees, inventory competitor's sales, on line purcharse and more.