A database is an organized collection of data. [1] It is the collection of tables,queries,reports,views and other objects. The data is tpicall organiz !odel aspects of realit in a wa that supports processes requiring infor!ati as !odelling the availabilit of roo!s in hotels in a wa that supports findi with vacancies. Database management systems (DBMS) are co!puter software applications that interact with the user, other applications, and the database itself to captur analze data. A general"purpose #$%& is designed to allow the definition, cre quering, update, and ad!inistration of databases. 'ell"(nown #$%&s include %&)*, +ostgre&)*,%icrosoft &)* &erver , racle , &base and I$% #$-. database is not generall portable across different #$%&s, but different #$%& interoperate b using standards such as &)* and #$ or /#$to allow a singl application to wor( with !ore than one #$%&. #atabase !anage!ent sste!s are often classified according to the database !odelthat the support0 the !ost p database sste!s since the 1 23s have all supported the relational !odel as represented b the &)* language. &o!eti!es a #$%& is loosel referred to as a 4database4. Data hierarchy refers to the sste!atic organization of data, often in a hier for!. #ata organization involves fields, records, files and so on. [1] A data field holds a single fact or attribute of an entit. onsider a date 5&epte!ber 1 , -3365. This can be treated as a single date field 7e.g. birthd fields, na!el, !onth, da of !onth and ear. A record is a collection of related fields. An :!ploee record !a contain a field7s8, address fields, birthdate field and so on. A file is a collection of related records. If there are 133 e!ploees, then e e!ploee would have a record 7e.g. called :!ploee +ersonal #etails record8 a the collection of 133 such records would constitute a file 7in this case, cal :!ploee +ersonal #etails file8.
Adatabaseis an organized collection ofdata.[1]It is the
collection of tables,queries,reports,views and other objects. The
data is typically organized to model aspects of reality in a way
that supportsprocessesrequiring information, such as modelling the
availability of rooms in hotels in a way that supports finding a
hotel with vacancies.Database management systems (DBMS)arecomputer
softwareapplications that interact with the user, other
applications, and the database itself to capture and analyze data.
A general-purpose DBMS is designed to allow the definition,
creation, querying, update, and administration of databases.
Well-known DBMSs includeMySQL,PostgreSQL,Microsoft SQL
Server,Oracle,SybaseandIBM DB2. A database is not
generallyportableacross different DBMSs, but different DBMS can
interoperate by usingstandardssuch asSQLandODBCorJDBCto allow a
single application to work with more than one DBMS. Database
management systems are often classified according to thedatabase
modelthat they support; the most popular database systems since the
1980s have all supported therelational modelas represented by
theSQLlanguage. Sometimes a DBMS is loosely referred to as a
'database'.Data hierarchyrefers to the systematic organization of
data, often in a hierarchical form. Data organization involves
fields, records, files and so on.[1]Adata fieldholds a single fact
or attribute of an entity. Consider a date field, e.g. "September
19, 2004". This can be treated as a single date field (e.g.
birthdate), or 3 fields, namely, month, day of month and
year.Arecordis a collection of related fields. An Employee record
may contain a name field(s), address fields, birthdate field and so
on.Afileis a collection of related records. If there are 100
employees, then each employee would have a record (e.g. called
Employee Personal Details record) and the collection of 100 such
records would constitute a file (in this case, called Employee
Personal Details file).Files are integrated into adatabase.[2]This
is done using a Database Management System.[3]If there are other
facets of employee data that we wish to capture, then other files
such as Employee Training History file and Employee Work History
file could be created as well.
