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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Running two MySQL servers that use the same data directory

The situation I have two MySQL instances, deployed on two different remote machines. Both MySQL instances access the same data directory, which is stored on a persistent volume (this volume is provided by Gluster, but that's not really relevant, I'm…
MikiTesi
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Oracle 11gR2: ORA-01102: cannot mount database in EXCLUSIVE mode

I am running Oracle 11gR2 on an AIX box. I did a rename database and change DB ID using NID. I can restart db in a nomount mode, but I can not mount it by the following error. ORA-01102: cannot mount database in EXCLUSIVE mode ALTER DATABASE OPEN…
dave
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Copying CSV file to temp table with dynamic number of columns?

I am wondering if there is a way to copy a csv file into a temp table where the number of columns is unknown in the csv file. The DB software I'm using is PgAdmin III. I figured out that if I do know the number of columns then I can create a temp…
Bmoe
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FileWatcher Troubleshooting Options

I have setup a Credential/Procedure/Program/File Watcher/Job to monitor a folder for new files, but it is not working. I am trying to figure out what I can check to troubleshoot why this isn't working. After scaling back the code to a bare…
Leigh Riffel
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Will Postgres handle the Unix Epoch problem?

I was wondering if Postgres will be handling the unix epoch problem coming in 2038? I have read about this and am wondering. It's about a productivity thing obviously because it is so far away, but I am curious.
Daniel L. VanDenBosch
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Does the term "page" have the same meaning in DBMS and OS jargons?

I am learning the data format of DBMS and found we have a term: page. Pages are the fetched data in main memory from external storage (eg. a disk, SSD) and several pages would be "cached" firstly to the Low Level Cache, when these pages are…
Jigao
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What DBMS to choose for my production environment?

This is my very first question on the StackExchange/StackOverflow community. I originally am an electrical engineer so I hope you bear with me. I need to set up a database whose purpose is to be interfaced with a software tool that will be created…
ryancooper73
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How do graph databases differ from older navigational (hierarchical/network) databases?

I'm trying to improve my knowledge of graph databases, in particular DGraph. Are graph DBMSs just a new generation of pre-relational hierarchical/network model DBMSs, or is there something new at a low level in the current generation of graph DBMSs…
webstackdev
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Can independent applications cause roll back to each other's transactions?

I have a database built on SQL Server Application-1 [Legacy App]: Written in C#, and runs transactions on the above database. Application-2 [New application being developed]: Written in Python, and runs transactions on the above…
Amit Tomar
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What is the best way to store a lot of user-encrypted data?

I'm about to develop an application that will mainly store user-encrypted data. Each piece of data being encrypted thanks to an AES key, itself encrypted with the public RSA key of each granted user. Given that the volume of non-encrypted data is…
Antoine Pinsard
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Error Code: 1239. Incorrect foreign key definition for 'foreign key without name': reference and table don't match

I'm making a new database in MySQL in which after making the Department table I receive an error when adding other tables. CREATE TABLE Department (dept_name varchar(20), building varchar(15), budget numeric(12,2), primary key(dept_name)); CREATE…
Chaos Order
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Does 3NF require 2NF?

I am a bit confused with the definition of 3NF. According to Wikipedia: The third normal form (3NF) is a normal form used in database normalization. 3NF was originally defined by E.F. Codd in 1971. Codd's definition states that a table is in…
Sunny
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What is the difference between covering and overlapping constraints use in DBMS?

What is the difference between covering and overlapping constraints use in DBMS?
dgcharitha
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Where sk = null clause gives an error when used in a query but not in a stored procedure in teradata

In teradata sql I get an error when I use sel * from table where sk = null However if I include this in a stored procedure and pass a null value in the parameter I don't. replace procedure(In name Integer,...) .... local = sel * from table where sk…
iosdev
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