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RDBMS

A relational databaseis a database that organizes information into one or more tables. Here, the relational database contains one table.

A table is a collection of data organized into rows and columns. Tables are sometimes referred to as relations. Here the table is celebs.

A column is a set of data values of a particular type. Here, id, name, andageare the columns.

A row is a single record in a table.

All data stored in a relational database is of a certain data type. Some of the most common data types are:

  • INTEGER, a positive or negative whole number
  • TEXT, a text string
  • DATE, the date formatted as YYYY-MM-DD
  • REAL, a decimal value

SQL Databases​

  1. Oracle Database
  2. MySQL
  3. Microsoft SQL Server
  4. IBM DB2
  5. Postgres

MySQL​

  • MySQL is the most popular open source SQL database. It is typically used for web application development, and often accessed using PHP.
  • The main advantages of MySQL are that it is easy to use, inexpensive, reliable (has been around since 1995) and has a large community of developers who can help answer questions.
  • Some of the disadvantages are that it has been known to suffer from poor performance when scaling, open source development has lagged since Oracle has taken control of MySQL, and it does not include some advanced features that developers may be used to.

Oracle DB​

  • Oracle corporation owns Oracle DB, and the code is not open source.
  • Oracle DB is for large applications, particularly in the banking industry. Most of the world's top banks run Oracle applications because Oracle offers a powerful combination of technology and comprehensive, pre-integrated business applications, including essential functionality built specifically for banks.
  • The main disadvantage of using Oracle is that it is not free to use like its open source competitors and can be quite expensive.

Bi-Directional Replication

SQL Server​

  • Microsoft owns SQL Server. Like Oracle DB, the code is also close sourced.
  • Large enterprise applications mostly use SQL Server. The key difference between Oracle and SQL Server is that SQL Server only supports the Windows Operating System.
  • Microsoft offers a free entry-level version calledExpressbut can become very expensive as you scale your application.

SQL Server Integration Service (SSIS)​

SQL Server Integration Services(SSIS) is a component of the Microsoft SQL Server database software that can be used to perform a broad range of data migration tasks.

SSIS is a platform for data integration and workflow applications. It features a data warehousing tool used for data extraction, transformation, and loading (ETL). The tool may also be used to automate maintenance of SQL Server databases and updates to multidimensional cube data.

First released with Microsoft SQL Server 2005, SSIS replaced Data Transformation Services, which had been a feature of SQL Server since Version 7.0. Unlike DTS, which was included in all versions, SSIS is only available in the "Standard", "Business Intelligence" and "Enterprise" editions.With Microsoft "Visual Studio Dev Essentials" it is now possible to use SSIS with Visual Studio 2017 free of cost so long as it is for development and learning purposes only.

https://en.wikipedia.org/wiki/SQL_Server_Integration_Services

SQL Server Reporting Service (SSRS)​

SQL Server Reporting Services (SSRS) provides a set of on-premises tools and services that create, deploy, and manage mobile and paginated reports.

https://www.toptal.com/sql/oracle-sql-server-differences

https://www.toptal.com/sql/oracle-sql-server-migrations-pt-2

https://www.toptal.com/sql/oracle-sql-server-migrations-pt-3

Codd's 12 rules​

Codd's twelve rulesare a set of thirteen rules (numbered zero to twelve) proposed by Edgar F. Codd, a pioneer of the relational model for databases, designed to define what is required from a database management system in order for it to be considered relational, i.e., a relational database management system(RDBMS).They are sometimes jokingly referred to as "Codd's Twelve Commandments".

  • Rule 0: The foundation rule
  • Rule 1: The information rule
  • Rule 2: The guaranteed access rule
  • Rule 3: Systematic treatment of null values
  • Rule 4: Dynamic online catalog based on the relational model
  • Rule 5: The comprehensive data sublanguage rule
  • Rule 6: The view updating rule
  • Rule 7: Possible for high-level insert, update, and delete
  • Rule 8: Physical data independence
  • Rule 9: Logical data independence
  • Rule 10: Integrity independence
  • Rule 11: Distribution independence
  • Rule 12: The nonsubversion rule

https://en.wikipedia.org/wiki/Codd%27s_12_rules