19 January 2023
19 January 2023

PostgreSQL Basics: Roles and Privileges

Information security, whether in databases, applications, or larger IT systems, is based on the principles of Authentication and Authorization, often referred to as AuthN and AuthZ respectively. Likewise, PostgreSQL security involves creating roles that allow access to server resources (AuthN) and then granting privileges to database objects appropriately (AuthZ). Understanding how each of these components work together is essential to effectively manage security in a PostgreSQL cluster.… Read more
17 January 2023
17 January 2023

Manage Data Over Time with SQL Server MERGE Statement

Once data is in a table it needs to be maintained. New records will need to be added, and existing records will need to be updated, and/or deleted. To keep data maintained, the insert, update or delete actions may need to be performed. This article will show how those three data manipulation language (DML) actions can be synchronized together within a single basic MERGE statement.… Read more
09 January 2023
09 January 2023

Index Types in PostgreSQL: Learning PostgreSQL with Grant

As with any other relational data management system (RDBMS), PostgreSQL uses indexes as a mechanism to improve data access. PostgreSQL has a number of different index types, supporting different behaviors and different types of data. In addition, again, similar to other RDBMS, there are properties and behaviors associated with these indexes. In this article I’m going to go over the different types of indexes and some index behaviors. We’ll get into what the indexes are, how they work, and how best you can apply them within your databases. I’m hoping you’ll develop an understanding of which indexes are likely to work better in each situation.… Read more
05 January 2023
05 January 2023

Introducing the MySQL common table expression

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As with many relational database management systems, MySQL provides a variety of methods for combining data in a data manipulation language (DML) statement. You can join multiple tables in a single query or add subqueries that pull data in from other tables. You can also access views and temporary tables from within a statement, often … Read more
02 December 2022
02 December 2022

Subqueries in MySQL

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A subquery is a type of query that is embedded—or nested—into a data manipulation language (DML) statement. The data returned by the subquery is passed into the DML statement and incorporated into its overall logic. The subquery itself is typically a SELECT statement, although you can also use a TABLE statement or VALUES statement. Even so, the SELECT statement continues to be the most common choice for subqueries, and that’s the one I focus on in this article.… Read more
12 November 2022
12 November 2022

Introducing the MySQL DELETE statement

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In the last few articles in this series, you learned about three important data manipulation language (DML) statements: SELECT, INSERT, and UPDATE. The statements make it possible to retrieve, add, and modify data in a MySQL database. Another DML statement that is just as important is DELETE, which lets you remove one or more rows from a table, including temporary tables. In this article, I focus exclusively on the DELETE statement to help round out our discussion on the core DML statements in MySQL. Overall, the DELETE statement is fairly basic, but one that’s no less necessary to have in your arsenal of DML tools. … Read more
26 October 2022
26 October 2022

Oracle optimizer Or Expansion Transformations

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The previous installment of this series examined aggregate subquery removal and subquery coalescing, describing the latter as similar in some ways to an inverse for “Or Expansion” and “Join Factorization”. In this instalment, it’s time to take a closer look at Or Expansion and we’ll move on to Join Factorization in the next instalment.… Read more
14 October 2022
14 October 2022

Backing up MySQL Part 1: mysqldump

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mysqldump is one of the most popular database backup tools in the MySQL world. The tool is prevalent partly because it’s very basic and quite powerful – mysqldump database backup tool is command line-based, very simple and very straightforward to use. As far as MySQL or its flavors (MariaDB and Percona Server) are concerned, this … Read more
07 October 2022
07 October 2022

Introducing the MySQL INSERT statement

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In the previous article in this series, I introduced you to the SELECT statement, one of several SQL statements that fall into the category of data manipulation language (DML), a subset of statements used to query and modify data. Another DML statement is the INSERT statement, which lets you add data to MySQL tables, both … Read more