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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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Circular foreign keys in PostgreSQL

I'm having a bit of an issue with circular foreign keys. I have a table posts with a uid column that is a BIGINT NOT NULL PRIMARY KEY, and I need to reference that in the last_seen_post column of my users table. The problem is that there's a…
Nocturn9X
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How could I DRY this SQL which UNION ALL two similar statements?

I need to UNION the results of the same SELECT code over two different schemas. (Example below.) But every time I need to change something in the code, I have to change it twice. I've already been bitten for forgetting to make the change in the…
Pahbloo Marks
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Solr index for RDBMS with jdbc driver

I believe i can create a Solr index for data in RDBMS using dataImportHandler. But I am not sure how to keep the index in sync when the table is updated (new data added,data deleted etc.) I am using Solr for full-text search for a particular table…
Prim
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Matching a pair of foreign keys in MySQL/SQL

Is there a way to pair foreign keys to match? E.g. The user_id and subs_id fk pair doesn't match in the product table but was allowed to be added. Table: user | user_id (PK) | first_name | last_name | | -------------| ------------|------------| |…
Andy Fazulus
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converting a sql query without sub query

Is there a way to convert this query into one without having the subquery in where clause? select distinct ie.install_id , ie.sp_id , ie.device_config_id from d1_sp sp inner join install_evt ie …
Punter Vicky
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How to create sub-table in tables group by one column?

I have been doing SQL and I am stuck in one point. For example, lets say we have a Table Employee with columns Emp_ID(varchar), DELIVERY_TIME(date),…
Raghav
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AWS DMS not able to migrate some tables between MySQL databases

I am migrating AWS RDS MySQL instance to another AWS RDS MySQL instance using Data migration service (DMS). Found below tables in mysql and performance_schema databases are not migrating and giving an error with pending validation in DMS table…
Prime
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this Subquery returned more than 1 value. This is not permitted when the subquery follows =, !=, <, <= , >, >=

i wrote a query to get total count of devices for user. but when i run the query for single user it working fine. when i keep mutiple emailids its not working getting message subquery should not contain multiple. I unable to change below query to…
rajesh
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there are two candidate keys but Primary key is not a composite key then the given relation is in 2nf or not?

Customer table having attributes (id, name, email, password, mobile). There are two candidate keys one is id, and the other is email, but the primary key is only id. customer_table
Mariya Mariya
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Dynamic SQL Query to read the jSon file or string using OpenjSon

I have a very large JSON string. I am trying to read using SQL for some report, but the JSON has objects embedded within in at least couple of levels. How can I read all the Data using one SQL query using OpenJson? I tried in the following…
AbdulAleem
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Why are relational databases needed?

Specifically thinking of web apps, (1) why are relationships(ie:foreign keys) in RDBMS even useful? The web apps I write have logic built-in that validates user input against required fields. I see no real use for foreign keys and thus no real use…
Brenden
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oracle 12 c Document Store RDBMS VS NoSql

I want to know oracle 12 c Document Store RDBMS VS NoSql I think that the Oracle 12c DocumentStore works similarly to MondoDB(schemaless-database). But today I heard a shocking story. Oracle12C database works similar to RDBMS. oracle12c…
ajflajfl13
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How to count repeated project_no in mysql

imagine i have 3 table employee detail, project details and Works on(where it's set that which employee will work on which project). The question is To show the average salary of all the employees work on those project which are having more than…
saman
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Managements wants to display city and manager details if more than one manager from same city

Refer the following table:resort management system Following query is used to retrieve the details: select distinct m1.city, m1.name, m1.phone from manager m1 join manager m2 on m2.city=m1.city where m1.name!=m2.name order by 1,2; I…
Swapnesh
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When using BigQuery/Snowflake do you write traditional SQL queries?

I have an advanced background in SQL (Postgres,Presto,MySQL,etc...) but am trying to teach myself technologies like BigQuery for a job and want to gauge my preparedness. My question is simply when querying in BigQuery or Snowflake do you write in…
Griffin Weinhold
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