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Questions tagged [rdbms]

A relational database management system (RDBMS) is a database management system (DBMS) in which data is stored in tables and the relationships among the data are also stored in tables.

A relational database management system (RDBMS) is a database management system () that is based on the relational model as introduced by E. F. Codd, of IBM's San Jose Research Laboratory. Many popular databases that are currently in use are based on the relational database model.

RDBMSs have become a predominant choice for the storage of information in new databases used for financial records, manufacturing and logistical information, personnel data, and much more. Relational databases have often replaced legacy hierarchical databases and network databases because they are easier to understand and use. However, relational databases have been challenged by object databases, which were introduced in an attempt to address the object-relational impedance mismatch in relational database, and XML databases.

History:
The development for the RDBMS model began at in 1974
The first commercially available RDBMS system was in 1979
The first RDBMS system for Mac OS was in 1984

References:

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How to merge rows and form multivalued attributes for a 2 column table in MySQL

I know this is terrible practice indeed, but I want to use the merged multivalued table for the GUI part of my program. Following is the thing I want. raw table to something like multivalued merged table Thanks in advance !!
Sagar Pingale
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OPENJSON unable to parse Portuguese characters

I'm trying to convert my JSON data into a table format in SQL Server Express 2019. Following are my JSON data: DECLARE @token INT; DECLARE @ret INT; DECLARE @url NVARCHAR(MAX); DECLARE @json AS TABLE(Json_Table NVARCHAR(MAX)) …
Hugo Pereira
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Why wouldn't you set activate_all_roles_on_login?

I'm just getting my toes wet in MySQL DBA and created some users and assigned roles to them. It took me a long time to realize that this on its own didn't result in the user assuming the roll when they login. This led me to learn about…
strikerdude10
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Get last value based on a condition on ordered table in SQL

I have a table representing product groups. Groups are defined by row number and their Type. Hence here we have 2 groups, the group is defined by the Type A, the Type B being components. Row…
tmhnr
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Retrieve top selling products

I would like to receive top 5 selling products in quantity in an order from NorthWind database. The database has a bunch of tables like Order, OrderDetails, Customers, etc. I was suggested to use Orders Details table below: Now, I tried the…
Avv
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ADD COLUMN with CONSTRAINT

I have a table name Stu_d. In this, I have created 3 columns {Stu_id INT PRIMARY KEY, Name VARCHAR(20), Roll_no INT(5)}. I need to add 1 more column with the name of Mobile_no with INT data type and have a constraint of UNIQUE KEY. With the help of…
Vasu Gupta
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Oralce uncommitted data in other sessions violating unique constraint leading to never-ending query

I am running into never ending update when there's uncommitted data in other session violating unique constraint. Here's the scenario: Say a table t has a unique contraint on one of its columns: CREATE TABLE T AS SELECT 'PIPE'||level AS CODE, level…
DeekuSen
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How to run multipe Oracle DBMS_SCHEDULER jobs in same session asynchronously

Is it possible to run multiple dbms_scheduler jobs in same database session asynchronously? The objective here is - Say we have two jobs JOB_1 and JOB_2 and they are modifying the same table. The data updated by JOB_1 (but not committed yet) should…
DeekuSen
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How do I retrieve Vertica Data in Parquet? locally

I'm trying to export data from my vertica DB to my laptop's local storage. Is this possible? When I tried the directory = 'C:/Downloads' it showed dir not found error. What's the alternative to directly retrieve data to local in parquet? Doc for…
Shivam Anand
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Getting Empty Set in MySQL on using "not in"

I'm a beginner at MySQL. Due to this, there may be some errors. I have an employee department database for learning purposes. I have stored the supervisorENO for employees who have got a supervisor. If an employee does not have supervisor, their…
Amartya Sinha
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Disambiguating columns used in group by that come from select

Assume a table person exists with columns id, first_name, last_name and table 'dog' exists with columns id, owner_id, name exist. Take the following query: Select first_name + last_name as name, count(*) dog_count from person join dogs on…
Darinth
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What's the most efficient way to find products that have sold less than 20 units in past year? (SQL)

Suppose I have two tables: CREATE TABLE products ( product_id NUMBER PRIMARY KEY, available_from DATE NOT NULL ); CREATE TABLE orders ( order_id NUMBER PRIMARY KEY, product_id NUMBER NOT NULL, quantity NUMBER NOT NULL, …
Jack
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Determine completeness of data supplied to RDBMS in multiple stages

Currently, I am writing an application that collects data in multiple stages. Suppose the entity: person. I might collect a portion of the data in one stage: name, address. And in some later state I might collect the supplementary the data: age,…
sander
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When we create a clustered index does it takes extra space?

I am asking this question with repect to mysql database.I read that clustered index orders the table based on primary key or columns that we provide for making clustered index, where as in non clustered index there is separate space taken for key…
PING
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How to check TIMESTAMP format in SQL?

What's the best way to check if the VARIANT TYPE with JSONs with value similar to TIMESTAMP_NTZ has correct format? For example, this is the correct format that I would like to have 2020-12-26T12:12:11.215581Z but there are times when it looks…
Tims
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