Questions tagged [rdbms]
Relational Database Management System, a widely used type of database management system characterised by its extensive use of joining as a core operational principle.
215
questions
-3
votes
1
answer
46
views
MYSQL workbench like gui tool for oracle 10 g or more
I am a java full stack developer who want to write oracle sql queries to simplify writing is there any mysql workbench like similar gui tool for oracle by oracle or any other please sugest
0
votes
1
answer
34
views
What makes many NoSQL databases non-ACID compliant when both SQL and NoSQL can scale horizontally
A lot of the difference between SQL and NoSQL that is talked about focuses on the fact that SQL support ACID properties while in many NoSQL dbs ACID is compromised.
I'm unsure of the reason but ...
- 117
0
votes
1
answer
42
views
NoSQL vs SQL during sharding when a single read operation only hits one shard
I've a use case where I'm stuck between figuring out whether to use SQL or NoSQL db.
The db has 2 fields - A (PK), B
A is 8 char-long, while B is 100-400 char long.
The operations are simply:
Write: ...
- 117
-2
votes
2
answers
52
views
Why is it a bad idea to have multiple values in a column in a relational database?
One problem I've found is slow database queries. If I had a table that had a column titled customer and another column titled grocery_items that contained multiple grocery items, then a simple query ...
2
votes
2
answers
70
views
How is data read in Cassandra when some columns are not mandatory compared to RDBMS?
I am not sure how to put my question in a proper databse terminology. But here it is.
My understanding of data reading in relational database:
In relational databases, as all columns are present, so ...
- 123
1
vote
1
answer
28
views
RDBMS performance on updating an index key(non primary)
I am creating a scheduler service for which I am using RDBMS(Mariadb, engine:InnoDB), which has following schema for jobs table
CREATE TABLE `jobs` (
`id` bigint(11) unsigned NOT NULL AUTO_INCREMENT,...
- 111
0
votes
0
answers
48
views
Top reasons for temp tablespace to go offline
It was marked offline and it is fixed already.
We want to know the list of causes that marks the temp tablespace offline.
0
votes
1
answer
45
views
What does relational capabilities mean in Codd's Foundation rule?
From Codd's 12 rules (emphasis mine):
For any system that is advertised as, or claimed to be, a relational
data base management system, that system must be able to manage data
bases entirely through ...
- 131
0
votes
2
answers
217
views
What's inside a redo record in Oracle's Redo log?
While reading the Redo log wiki page, I was confronted with the following statement:
For example, if a user UPDATEs a salary-value in a table containing employee-related data, the DBMS generates a ...
- 131
0
votes
0
answers
296
views
AWS Athena generic internal error when querying a table Glue created because 'columns has 110 elements while columns. Types has 106 elements!'
This error happens to me anytime I try to query the 'airports' table in my database which was created by a glue crawler I created for this purpose along with 3 other datasets. They were all csv files ...
- 227
0
votes
1
answer
25
views
In RDBMS(MySQL..), the more complexity was added to the query, the higher time the query will take?
The complexity includes these factors:
Number of joined tables
Number of subqueries
Number of aggregate functions
Number of groups by, the columns in group by, the window functions
Number of where ...
- 3
1
vote
2
answers
135
views
Update Ledger Table In double entry accounting when there are millions of entries
I am creating an double entry accounting software where I have ledger table along with other tables. My cash account ledger table for is similar to following:
ledger_id
ledger_name
...
1
vote
1
answer
698
views
What difference between columnar and wide column databases?
What difference between columnar database (AWS Redshift, Azure Synapse, GCP Bigquery, Snowflake) and wide column database (AWS Keyspaces, Azure CosmosDB, GCP Bigtable, Hbase, Cassandra)?
What I ...
- 61
0
votes
1
answer
48
views
How does MySQL maintain confidentiality of files?
In a DBMS like MySQL, are the underlying files that contain the data encrypted since we want to have role and user based control? If they are encrypted, what encryption keys and algorithms are used? ...
- 101
-1
votes
1
answer
70
views
How to handle a constantly changing schemas and tightly coupled entities (ORM hell)?
Essentially my team's ended up in a situation where Object A, B, C, D, and E (greatly simplified *sigh*) are different Java objects and each is represented by a single table interconnected with other ...
- 99
1
vote
2
answers
570
views
MySQL distinct select for emoji always return 1 emoji out of 2
I have these emojis stored in a reaction column. 😏, 😇
If I run this query:
SELECT DISTINCT reaction
FROM chat_reactions
WHERE chat_id = 593
it only selects the first one. My column's collation ...
- 111
2
votes
1
answer
59
views
Are there better alternatives to a time series databases for managing financial transactions?
We are considering using AWS Timestream to store financial transactions from various sources for users. Any solution needs to be able to support ~4k transactions per user per year for 1 million users. ...
- 21
0
votes
1
answer
92
views
About Transaction knowledge
Am teaching myself SQL. And I never worked in any enterprise company but I have watched and learned some tutorials about web development and I see crud applications used to inject data into a database ...
-2
votes
1
answer
392
views
What prevents relational databases from being optimized for writes rather than reads?
I noticed that most of the popular relational databases systems such as PostgreSQL, MySQL, MariaDB, SQLite, etc. are oriented towards reads rather than writes. It seems that many of these database ...
- 107
0
votes
1
answer
217
views
How many keys in mySql are too many?
I am currently designing a MySQL database that has 212 tables. Some of the tables has 5-7 foreign keys. Is this going to hamper database query performance in the long run? How many foreign keys are ...
0
votes
1
answer
37
views
In general if you were to index all columns would that be the same as indexing no columns?
The title likely sums up my question, but to be clear, I'm specifically thinking RDBs.
I have no intention of doing this, I've just been curious and haven't found a clear answer in my attempts at ...
- 127
8
votes
3
answers
3k
views
Why is it more difficult to horizontally scale a relational database than a NoSQL database like MongoDB?
Is the main reason for the difficulty in horizontally scaling / distributing an RDBMS because of an adherence to ACID transactions? Is it the fact that multiple tables are so interconnected, or ...
- 191
0
votes
0
answers
18
views
Should I use many database in one application?
Currently I am working on a project of a management software. This software is currently in built with an old technology (Codeigniter-PHP). My job is to convert this software to latest technology (...
1
vote
3
answers
301
views
SQL or/with Nosql
I am designing a mobile app with basic functionality such as sign-up, Auth, posts, real time messages etc. I think for this kind of work Nosql should work better. But over a long period of time I want ...
- 23
1
vote
1
answer
2k
views
Why do we need a Unique key when we have a Primary key?
I tried to Google this question but all I found were differences between primary and unique keys, why do we actually need a unique key when we have a primary key that can identify any single record, ...
- 21
0
votes
0
answers
321
views
E-R diagram 1-to-1 mandatory relationship for two superclass entities to relational schema
How are two superclass entities that are connected to a mandatory 1-to-1 relationship converted to relational schemas? These two superclass entities are also abstract, meaning that they will not have ...
- 101
0
votes
1
answer
155
views
Right way to store several addresses and select one as main/principal
I'm working in a little model and I'm struggling with a simple question.
How should I store a list of addresses/mails/phones and select one as principal?
Example I'm thinking now.
AddressEntity:
Id
...
- 103
1
vote
0
answers
55
views
Is it a bad idea to make redundant rows when 2 columns reference to the same table?
Suppose we have this database design
Users table:
- id
- name
Friends table:
- id
- user_id
- friend_user_id
Let's say USER 1 befriended USER 2, this is what my application logic will execute:
...
- 111
0
votes
2
answers
174
views
Database: Splitting tables based on logically grouped optional columns
I keep having this argument with my management about splitting the tables. I prefer splitting a database table to multiple tables based on attributes that can be grouped together. The columns which ...
- 101
0
votes
1
answer
1k
views
create a trigger to update status on parent table based on values of child table
Table order
columns - id status
1 confirmed
Table trays
columns - id,orderid(fk),status
1 1 done
2 1 processing
I have to update the status of ...
- 25
0
votes
0
answers
52
views
RDB data combination table modeling
There's data and if I combine it, I need to get the corresponding result.
If I choose A and I got B,
If I choose B, I should also get A.
I want to save both data and combinations in DB, but it's hard ...
- 1
0
votes
1
answer
48
views
Relational or non-relational when dealing with highly relational, big data [closed]
I'm working on a project (in Java) that will be processing a large event stream (GBs every minute). This data is heavily processed to find relationships between events. This is done through a ...
- 103
3
votes
1
answer
460
views
Is using of subqueries more efficient than using Limit offset and order by in MySQL?
For instance, we have a problem of finding the employee with the second highest salary in the table.
This is my table
id name dept salary
1 Ram HR 10000
2 Amrit MRKT 20000
3 ...
- 93
4
votes
3
answers
471
views
Inconsistency in Relational Databases
I generally get confused when the term consistency is used. NoSQL tutorials always refer to the reads whereas Relational tutorials refer to a consistent state (ensuring referential integrity ...
- 161
0
votes
1
answer
950
views
MS Northwind Traders DB Inventory Transactions Entity relationship question
Trying to understand Northwind Traders' db schema but I cannot comprehend the relationship between:
Inventory Transactions<--->Purchase Order details
Inventory Transactions<--->Order ...
- 1
0
votes
1
answer
144
views
What could be the best DBMS to store airbnb data for price prediction [closed]
I have a school project in which I need to predict the airbnb listings prices in 5 different cities.
So I have about 400,000 records each with 19 columns.
All the examples on the internet that are ...
- 103
26
votes
4
answers
6k
views
If NoSQL stands for "Not only SQL", is SQL a subset of NoSQL?
The definition is a bit confusing - basically I'm asking if SQL is a subset of the NoSQl family:
I'm asking this because "Not-only" means NoSQL is much larger, but still includes SQL as a ...
- 465
1
vote
2
answers
1k
views
Best practice for "recycling" rows on PostgreSQL (UPDATE vs INSERT + DELETE)
I searched responses on "UPDATE vs INSERT + DELETE" in general terms and the consensus is UPDATE is faster, as expected.
My question is centered on a somewhat niche use case. Let's say you ...
- 111
0
votes
0
answers
55
views
Suggestion for NoSQL database for global users
We are planning to build a social media application, lets say similar to Instagram but at much smaller scale, of course.
The users could be from many geographies like US, Europe, Asia who could ...
- 101
1
vote
1
answer
57
views
How to get the row count from a table related to other table? [closed]
I am new to mysql and database concepts and I will try to explain my question through these two minimal tables, here is the scenario for which I need to write a query,
Table : Fruits
| FruitId | ...
- 13
2
votes
0
answers
1k
views
EAV vs JSON/XML column approach to store complex user form data in a database? [closed]
We are working on an internal tool which will essentially be a complex, power-user oriented form app. It is not a dynamic field app - users can't define their own fields.
Form field types: The form ...
- 166
0
votes
1
answer
190
views
Storing daily yield curve data in SQL table
I have daily yield curve data for integer maturities that should be stored in a MSSQL server.
Currency.csv
Currently, the data is stored in CSV files per currency in the format:
date, 1y, 2y, 3y, ...
...
- 165
5
votes
3
answers
3k
views
Why Cassandra is not considered a relational database?
Read this answer
Relational databases are based on the relational model, an intuitive, straightforward way of representing data in tables. In a relational database, each row in the table is a record ...
- 169
1
vote
1
answer
119
views
Storing dart throws in relation database (JSON vs multiple tables)
I'm trying to model database for storing dart throw practices.
Data sent from frontend will look something like this
[
{"target_name":"S13","singles":1,"doubles&...
- 13
0
votes
3
answers
1k
views
What are best practices for storing many iterations of a product in an RDBMS?
We are building a tool to track the prices of products over time, and using Postgres as our RDBMS. It is important that product attributes can be changed, and that the history of an product's ...
- 3
1
vote
2
answers
147
views
Detection of contradictions
I found some old notes of mine from 2011 and I also re-read the excellent article 10 Cool SQL Optimisations That do not Depend on the Cost Model by @lukas-eder. So I thought I would take my notes for ...
0
votes
2
answers
82
views
Multiple Primary-Foreign Key connections between Tables Redundant?
I have two tables, Reviews and Critic
I'm pretty new to RDBMS and I was wondering if the connection between Review.rID and Critic.Review is redundant?
My reasoning is that a single critic can have ...
-1
votes
1
answer
30
views
Database design normalization elearning portal
Table : Class
Here the className is unique
classId| className
-------|---------
1 | 1st Class
2 | 2nd Class
3 | 3rd Class
4 | 4th Class
Table: Subject
In the Subject table ...
- 101
0
votes
0
answers
26
views
Can parameter sniffing happen in other RDBMSs, not just SQL Server? [duplicate]
I just found out that when googling for the parameter sniffing, SQL server is also on the recommended search list but not other RDBMS such as Oracle, MySQL, PostgreSQL. Even in this community, ...
- 499
1
vote
1
answer
69
views
Merge two applications using different NoSQL databases
This is a very generic and high level set of queries related NoSQL type of datastores
Imagine I have two different applications using NoSQL datastores each hosting its own document collection.
...
- 111