Database Administrators Stack Exchange
Database Administrators Stack Exchange

Questions tagged [dbms]

Database management systems (DBMSs) are specially designed applications that interact with the user, other applications, and the database itself to capture and analyze data.

A general-purpose database management system (DBMS) is a software system designed to allow the definition, creation, querying, update, and administration of databases. Well-known DBMSs include MySQL, PostgreSQL, SQLite, Microsoft SQL Server, Microsoft Access, Oracle, SAP, dBASE, FoxPro, IBM DB2, LibreOffice Base and FileMaker Pro. A database is not generally portable across different DBMS, but different DBMSs can inter-operate by using standards such as SQL and ODBC or JDBC to allow a single application to work with more than one database.

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Does `COUNT` discard duplicates?

My professor taught me this SQL statement: SELECT COUNT(length) FROM product will return 2 with the following dataset: product |id | length | code | |-------------------| | 1 | 11 | X00 | | 2 | 11 | C02 | | 3 | 40 | A31 | She…
Jules Lamur
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Performing projection first and then selection?

Consider a simple query: Select username,usertype from Table1 Where usertype='Manager' Most probably the DBMS will be performing selection first, and then projection i.e. first pulling out rows form Table1 having usertype='Manager' Is there a case…
Usman Waheed
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Can a/some DBMS be installed as an OS

Is there any DBMS that can be installed as an OS instead of as an app on a OS? I wasn't able to find any. Later edit, just to clarify: I'm used to installing a DBMS (MySQL, MSSQL) as a server(ice) onto an OS(Windows, Ubuntu, etc.). I was trying to…
Rainer Retzler
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problem with selecting correct values from database

I have the following database and I'm having problems writing the correct select phrase. I am new to SQL and hope you could help me by showing me the correct way to select the desired data: Employee (eid, ename, salary, did,…
BeginningMath
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Determine Prime Attributes In this relation. Functional Dependencies are given

Relation is R(P,Q,C,A,B) R has the following functional dependencies: F = { P→QC , CA→B , Q→A , B→P } What are the prime attributes
Tanmay Bholane
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