HELLO GUYS... OKAY THIS IS THE ENTRIES OF DATABASE THAT SHOULD BE KNOWN BY CS STUDENT.

And fyi this chapter gonna be your multimedia test which is carry 15% of your PSPM.
BEST OF LUCK...
47 DAYS TO GO. 







 

Database

A database is a data structure that stores organized information. Most databases contain multiple tables, which may each include several different fields. For example, a company database may include tables for products, employees, and financial records. Each of these tables would have different fields that are relevant to the information stored in the table.
Nearly all e-commerce sites uses databases to store product inventory and customer information. These sites use a database management system (or DBMS), such as Microsoft Access, FileMaker Pro, or MySQL as the "back end" to the website. By storing website data in a database, the data can be easily searched, sorted, and updated. This flexibility is important for e-commerce sites and other types of dynamic websites.
Early databases were relatively "flat," which means they were limited to simple rows and columns, like a spreadsheet. (See also "flat file database"). However, today's relational databases allow users to access, update, and search information based on the relationship of data stored in different tables. Relational databases can also run queries that involve multiple databases. While early databases could only store text or numeric data, modern databases also let users store other data types such as sound clips, pictures, and videos.

DBMS

Stands for "Database Management System." In short, a DBMS is a database program. Technically speaking, it is a software system that uses a standard method of cataloging, retrieving, and running queries on data. The DBMS manages incoming data, organizes it, and provides ways for the data to be modified or extracted by users or other programs.
Some DBMS examples include MySQL, PostgreSQL, Microsoft Access, SQL Server, FileMaker, Oracle, RDBMS, dBASE, Clipper, and FoxPro. Since there are so many database management systems available, it is important for there to be a way for them to communicate with each other. For this reason, most database software comes with an Open Database Connectivity (ODBC) driver that allows the database to integrate with other databases. For example, common SQL statements such as SELECT and INSERT are translated from a program's proprietary syntax into a syntax other databases can understand.

Table (database)

A table is a collection of related data held in a structured format within a database. It consists of columns, and rows.
In relational databases, and flat file databases, a table is a set of data elements (values) using a model of vertical columns (identifiable by name) and horizontal rows, the cell being the unit where a row and column intersect.^[1] A table has a specified number of columns, but can have any number of rows.^[2] Each row is identified by one or more values appearing in a particular column subset. A specific choice of columns which uniquely identify rows is called the primary key.
"Table" is another term for "relation"; although there is the difference in that a table is usually a multiset (bag) of rows where a relation is a set and does not allow duplicates. Besides the actual data rows, tables generally have associated with them some metadata, such as constraints on the table or on the values within particular columns.^{[dubious – discuss]}
The data in a table does not have to be physically stored in the database. Views also function as relational tables, but their data are calculated at query time. External tables (in Informix^[3] or Oracle,^[4][5] for example) can also be thought of as views.

Flat file database

Example of a flat file model^[1]

A flat file database is a database stored as an ordinary unstructured file called a "flat file". To access the structure of the data and manipulate it on a computer system, the file must be read in its entirety into the computer's memory. Upon completion of the database operations, the file is again written out in its entirety to the host's file system. In this stored mode the database is said to be "flat", meaning that it has no structure for indexing and there are usually no structural relationships between the records. A flat file can be a plain text file or a binary file.
The term has generally implied a small, simple database. As computer memory has become cheaper, more sophisticated databases can now be entirely held in memory for faster access. These newer databases would not generally be referred to as flat-file databases.

Query

Query is another word for question. In fact, outside of computing terminology, the words "query" and "question" can be used interchangeably. For example, if you need additional information from someone, you might say, "I have a query for you." In computing, queries are also used to retrieve information. However, computer queries are sent to a computer system and are processed by a software program rather than a person.
One type of query, which many people perform multiple times a day, is a search query. Each time you search for something using a search engine, you perform a search query. When you press Enter, the keywords are sent to the search engine and are processed using an algorithm that retrieves related results from the search index. The results of your query appear on a search engine results page, or SERP.
Another common type of query is a database query. Databases store data in a structured format, which can be accessed using queries. In fact, the structured query language (SQL) was designed specifically for this purpose. Users can create SQL queries that retrieve specific information from a database. For example, an human resources manager may perform a query on an employee database that selects all employees in a specific department that were hired between 11 and 12 months ago. The results might be used to provide the department head with current candidates for an annual review.
While you may not always notice them, computer queries are happening all the time. For instance, most dynamic websites query a database each time you visit a new page. Software applications often contain background functions that perform queries based on your input. While many types of computer queries exist, their basic purpose is the same — to receive an answer to a question.
NOTE: The word "query" can be used as either noun or a verb. For example, you can "perform a search query" or "query a database." Both examples are correct uses of the word "query."

Record

A record is a database entry that may contain one or more values. Groups of records are stored in a table, which defines what types of data each record may contain. Databases may contain multiple tables which may each contain multiple records.
Records are often called rows since each new record creates a new row in the table. Individual fields are sometimes called columns since they are the same for each record within a table. While the words "record" and "row" are often used interchangeably, most DBMSes use the word "row" for database queries and error messages. Therefore, if you see an error message on a website that says "Unable to jump to row 89," for example, it means the record was not found in the database.
Records are an efficient way to store and access data. Since each record may contain multiple data types, a single record may include many different types of information. For example, a personnel record may contain an ID number, name, birthdate, and photo, which are all different data types. Individual fields within the personnel record can be easily accessed or compared with other records using a database query. Additionally, records can be easily created, modified, and deleted without affecting other data in the database.
NOTE: The word "record" is also a verb (pronounced "re-cord"), which means to capture and save audio and/or video data.

Field

A field is a user interface element designed for entering data. Many software applications include text fields that allow you to provide input using your keyboard or touchscreen. Websites often include form fields, which you can use to enter and submit information.
In software programs, the terms "field" and "text box" may be used interchangeably. For example, a world processor may provide several formatting options, such as font size, line spacing, and page margins. Each option includes a text box where you can manually enter custom settings. Many applications also include a search field (or "search box") that allows you to search the contents of one or more documents.
When you visit a website, it may provide a form that allows you to enter data, such as your billing address or registration information. Each single-line text box within a web form is called an "input" field and is defined by <input type="text"> in HTML. Fields with more than one line are called text areas and are created using the <textarea> tag. You may also encounter login forms that include two fields for entering your username and password. Most password fields are defined as <input type="password"> which hides the characters as you type.
NOTE: Databases also include fields. Each row or "record" in a database table may include multiple fields. The table columns define what fields are available in each row. Therefore, a specific column and row combination (such as Row: 101, Column: Name) defines a specific field. Individual fields in a database may be searched and modified using standard SQL queries.

Primary Key

A primary key is a unique identifier for a database record. When a table is created, one of the fields is typically assigned as the primary key. While the primary key is often a number, it may also be a text field or other data type. For example, if a database contains definitions of computer terms, it would make sense that each term is only listed once in the database. By defining the "Term" field as the primary key, it would ensure that no term is listed more than once in the database.
While a table's primary key is usually assigned to a specific field, it can also be comprised of multiple values. For example, a database of news articles might use both the title and date fields to uniquely identify each entry. By combining the "Title" and "Date" fields as the primary key, it would ensure no entries have the same title on the same day.
If multiple fields in a table cannot have duplicate values, most database management system (DBMS) also allow fields to be defined as "Unique." This is similar to setting a field as the primary key, but is not exactly the same thing. The primary key also acts as a pointer to the record and provides a simple way for the DBMS to search, sort, and access the records. It also helps relate records across multiple tables. Therefore, while multiple fields within a table can be defined as "Unique," each table can only have one primary key. The primary key field must also be defined for each record and not set to null. After all, a undefined identifier is not very useful.

Foreign Key

Definition - What does Foreign Key mean?

A foreign key is a column or group of columns in a relational database table that provides a link between data in two tables. It acts as a cross-reference between tables because it references the primary key of another table, thereby establishing a link between them.
The majority of tables in a relational database system adhere to the foreign key concept. In complex databases and data warehouses, data in a domain must be added across multiple tables, thus maintaining a relationship between them. The concept of referential integrity is derived from foreign key theory.
Foreign keys and their implementation are more complex than primary keys.

 
 

THIS ENTRIES FOLLOWED BY REFERENCE.


REFERENCE:

https://techterms.com/definition/field
https://techterms.com/definition/relational_database
https://techterms.com/definition/database
https://techterms.com/definition/record
https://techterms.com/definition/field
https://techterms.com/definition/primarykey
https://www.techopedia.com/definition/7272/foreign-key
https://en.wikipedia.org/wiki/Table_(database)
https://en.wikipedia.org/wiki/Flat_file_database