Relational Database Management System, a widely used type of database management system characterised by its extensive use of joining as a core operational principle.

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4
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181 views

How to model complex systems like networks in Postgres

I need help with modelling of a network involving switches (24 port, 48 port, POE, and a combination of those) and edge devices (computers, IP cameras, telephones). From an object oriented ...
0
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1answer
35 views

Can inserting new rows make the RDB not use an index?

Say I have a table with 10000 records. I then delete them and create them again. This is done with "normal" sql, row by row (not some sort of bulk insert (BCP in sqlserver lingua)). Does the ...
2
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2answers
49 views

Database design appoach confirmation

I am working for a mortgage company in migrating a legacy application to new application for managing claims, means lender fore close a loan and request for a claim to get its funds from government or ...
0
votes
1answer
26 views

Verbose Oracle RDBMS error log output examples?

I'm working on a project and my boss has asked that I find an actual example of the "verbose" output of an Oracle RDBMS query error. We want to see what they actually look like. I know that there are, ...
0
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1answer
64 views

Proof for this answer

I am not sure whether this is offtopic. However, please read on. A person whom I know has encountered a problem in the answer key published by CBSE, India. As their key challenging form contains a ...
2
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2answers
211 views

Is it acceptable to have circular foreign key references\How to avoid them?

Is it acceptable to have a circular reference between two tables on the foreign key field? If not, how can these situations be avoided? If so, how can data be inserted? Below is an example of ...
2
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1answer
100 views

Why do we need partitions in PostgresSQL? (or any other RDBMS)

So, I am trying to teach myself partitions in PostgreSQL. I understand that a database can become slow when a table hits millions+ of lines and indexes don't fit into memory anymore. One thing that ...
0
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0answers
26 views

Why isn't user being shown in DBA_USERS?

I have created a user and I wanted to know it's default_tablespace but whenever I run SELECT query for showing default_tablespace or anything it says no rows selected.How can I resolve this issue? ...
0
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0answers
27 views

Modeling attributes relations in RDBMS/NOSQL?

I have a table to hold the relationship between attributes and documents: I need to support the following queries : give all documents where attrib X='value' give me all documents where attib ...
1
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1answer
47 views

Need Help in building database

I am developing an app that send messages (email and sms) to users. The db must also maintains the list of messages send to users. And also the status of messages send to user like send or failed. I ...
0
votes
1answer
25 views

How to store external IDs from different sources?

I have a table of customers with a PK that we can use as an identifier for our internal system. These customers may belong to different companies, each of which may have an external ID in some ...
0
votes
1answer
62 views

Help writing the following query to relational algebra

Can someone help me in writing the following query to relational algebra, I am studying DBMS and I am stuck on this exercise. Query: SELECT a.name, d.name. d.grade FROM student a, enrolled i, class ...
2
votes
2answers
1k views

How to insert values in junction table for many to many relationships?

I have three tables in database: trips(trip_id(pk), trip_name(unique), user_id(fk)) places(place_id(pk), place_name(unique)) trips_places_asc(trip_id(fk), place_id(fk)) Since many trips can ...
0
votes
2answers
81 views

Need help about giving relationships in database design

I am developing a simple blog application in which users can write posts and others can like, comment, share etc. i am facing difficulty in designing database. What I have tried is: user ...
3
votes
3answers
575 views

How to achieve many to many relationship in this database design?

I am currently working on small travel application in which users can add other users' trips in their wishlist. I am facing difficulty in designing database for wishlist. What I have tried so far is: ...
0
votes
1answer
27 views

Which foreign keys do I use if they are repeated

I have the following two tables company_relationships |ID|Company_ID|Affiliate_ID|<Relationship Info>| +--+----------+------------+-------------------+ jobs |ID|Company_ID|<Job Info>| ...
0
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0answers
28 views

How to store highly configurable relationships based on multiple conditions

I'm trying to devise a schema that needs to be extremely configurable when necessary, but also minimal wherever possible. There is a large number of condition types that would lead to a number of ...
0
votes
1answer
52 views

Oracle dataguard - Redo apply

In a low bandwidth environment when a transaction commits that generates a large amount of redo data will cause other independent transactions to slow down. This is because the redo data of small ...
1
vote
1answer
267 views

Running queries directly on DB2 databases

Just have a general query, if it is really fine or safe to run long select queries on RDBMS production Databases specifically DB2? If NO, what are the major risks and issues in executing select ...
2
votes
2answers
346 views

What is the advantage of using numeric primary keys in a relational database?

Many tables in a relational database system (in my admittedly limited experience) have this sort of structure (Oracle syntax as that's what I'm used to): create table widgets ( widget_id number ...
0
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0answers
71 views

Need some feedback on simple RDBMS design Project

Project: Create a simple group system for a social networking website. My Idea: Group table (ADDED_BY_MEMBER_ID = ADMIN ) Group Member table (I was thinking of added a IS_ADMIN column here ) ...
2
votes
2answers
2k views

Improve MySQL Query Performance - Too many records

I am using MySQL RDMS for a contact management system. Now a days my database grew in size and contains more than 1 million records. Checking duplicate phone numbers became a big issue during ...
4
votes
1answer
150 views

Optimizing indexes

I just began optimizing my schemas with indexes (pretty late I guess). I never dealt with huge dataset but I'll be soon coping with about 1 to 5 millions rows. Here is the schema I'm using right now ...
0
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1answer
491 views

MySQL: What is SQL mode and why we use it

If in an application, if we execute sql_mode=mysql4.0 as a first query in my application but using MySQL 5.1 in my application then what will happen? Will my system use MySQL 4.0 or MySQL 5.1 ...
0
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1answer
60 views

why should use MongoDB [closed]

In which types of projects, MongoDB is the best suited? Can we use MongoDB in large applications? Why Open Source CMS and framework doesn't have support for MongoDB? How it is different than other ...
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0answers
68 views

Why NOSql should be more performant than RDBMS under structured data loads?

The main reason NoSQL dbms have become so common is the need of storing unstructured data where a Relational database instead would require carefully designing a database schema and fitting data into ...
0
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1answer
55 views

WHAT RDBMS ( SQL SERVER/ ORACLE ) close to manage MYSQL(DBA) [closed]

i have a requirement for learning MYSQL for DBA. here all training institutes teach on ORACLE AND SQL SERVER. SQL is mandatory to work on RDBMS. what RDBMS SYNTAX CLOSE TO MYSQL for DBA(backups, ...
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0answers
96 views

MySQL: What criteria should I base my table column order/arrangement/grouping on?

Does the order, arrangement or grouping of columns with large (such as long text descriptions) and small (such as bit and tinyint) field types have any noticeable impact on MySQL (InnoDB engine) ...
0
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1answer
259 views

Type of Foreign Keys for a Dimensional Model Fact Table?

I've been reading about dimensional models, and in particular fact tables, but I haven't really seen one in action (i.e. the actual content), just diagrams of the table structures and column names ...
1
vote
1answer
220 views

Database Design Concept - Are Multiple Relationships A Bad Thing?

I have a question about Relational Database design. I'm just learning the basics of databases, so bare with me, in that I'm not sure of the technical terms for some of the concepts I'm trying to ...
4
votes
2answers
458 views

how to create an incremental database copy in postgresql?

Virtual machine software like VirtualBox allow one to make incremental VM clones. That is data, once "touched" (opened writable), will be copied and stored in the incremental cache of the new clone. ...
0
votes
1answer
112 views

Two types of data, so two type of databases?

For a social network site, I need to propose a DB. The application is written in Java & will be hosted on VPS(s) initially. Broadly classified there is two type of data to be stored at backend: ...
6
votes
1answer
1k views

Full text search through many tables in MySQL

We have high traffic NEWS websites, I want to add a feature that every user can search through over all content of site, such as news, polls, comments, galleries,etc . Each of contents type has its ...
1
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1answer
30 views

Plan for storing transactions in an easily retrievable manner, indefinitely

I've got a large (many columns) MySQL database table (InnoDB) that has a fairly high number of INSERTs (~500/day). Think of the records as financial transactions. Clients need to be able to view these ...
0
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1answer
121 views

Database design in MySQL

I am designing a database for an web application, in this system there are multiple users. Consider, Public (Buyer). Merchant. Tele Marketing Executive(TME). Marketing Executive(ME). Lead ...
1
vote
1answer
499 views

How does Postgres know which logs have been archived?

I'm asking this because Postgres was hard-stopped yesterday, and I fear that there could be partial / corrupt data in one of my archived log segments. I'd like to simply delete the logs from my slave ...
0
votes
1answer
175 views

SQL Server automatic transaction log truncation

Have looked through msdn but cant find answers to these: Any help much appreciated: In simple recovery mode: Is there any TSQL or alternative functionality that will provide a notification either ...
4
votes
4answers
965 views

In Memory Database for high transaction and volume spikes on a website [closed]

I am looking at the IA for a hypothetical application scenario, for example: A high demand application such as an online ticketing website where there can be demand for 100,000 tickets to be ...
20
votes
6answers
2k views

Why don't databases create their own indexes automatically?

I would have thought that databases would know enough about what they encounter often and be able to respond to the demands they're placed under that they could decide to add indexes to highly ...
0
votes
2answers
233 views

Partitioning MySQL for “expired” transactions to improve performance

I am dealing with an existing application that uses the database as a sort of transaction log in several cases, for example orders or payments. These tables are large (20 - 60 million rows) and poorly ...
0
votes
1answer
535 views

How to perform ETL from RDBMS to Neo4j

I have a mature 50+ tables web application based on mySQL. In order to do some advanced data mining I want to use Neo4j and the goodnes of cypher. However I'm having a hard time migrating my data from ...
0
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2answers
277 views

Storing data in PostgreSQL: One table or two?

I've just started using PostgreSQL 9.2 and my data consists of product prices at various points in time, usually a different price every month. Question: Because every product can have different ...
0
votes
2answers
69 views

Accessing Database without using SQL

This might be some ambiguous but I have not much info about this so I need some start point; As a general idea; in conventional RDBMS', there are a DB engine and storage of data. We use the language ...
-1
votes
1answer
73 views

best database for a real estate system [closed]

Which is the best database suits for a real estate system. Considering the storage space, security, crash recoveries, speed etc. There will be around 1000 fields and trillions of rows!!!
46
votes
5answers
12k views

Which database could handle storage of billions/trillions of records?

We are looking at developing a tool to capture and analyze netflow data, of which we gather tremendous amounts of. Each day we capture about ~1.4 billion flow records which would look like this in ...
15
votes
1answer
5k views

Using MongoDB and PostgreSQL together

My current project is essentially a run of the mill document management system. That said, there are some wrinkles (surprise, surprise). While some of the wrinkles are fairly specific to the ...
1
vote
1answer
355 views

join the two tables which possess one to many relationship

In drupal,the content type table and my own table is used to do some operations. Im having two tables namely Table1:'content_field_mem_id' & Table2:'Ex' description of ...
6
votes
2answers
3k views

A database in MySQL is a schema in Oracle : I do not understand this statement

Please help me understand this statement: A database in MySQL is a schema in Oracle. I have just started to use Oracle and I find it different from other RDBMS softwares I have used like MSSQL, ...
3
votes
4answers
8k views

Why is optimistic locking faster than pessimistic locking?

Both forms of locking cause a process to wait for a correct copy of the record if its currently in use by another process. With pessimistic locking, the lock mechanism comes from the DB itself (a ...
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2answers
167 views

How does optimistic locking actually enforce re-read/update?

My understanding of optimistic locking is that it uses a timestamp on each record in a table to determine the "version" of the record, so that when the record is access by multiple processes at the ...