The MySQL database is without a doubt the most popular database already in existence. For MySQL developers, countless tricks, options and functions are available. Many technical and detailed content often surrounds developers and their mysql consulting services, that can easily distract them from the big picture of MySQL. The problem is they lack a checklist of all the techniques that are essential to master. I developed and standardized a lot of MySQL databases (along with IT consulting) that motivated me to write this article. The following are 10 essential mysql query optimization tricks or things any serious MySQL developer should know about:
- Do not edit dump files
If you’ve ever seen mysql dump’s dump files, they look a lot like regular, harmless text files. But they quickly learned that they are anything but a text file for anyone who has ever tried to edit them. In a standard text editor, most people edit them, and then the corruptions begin to appear. Leaving the dump files alone is the only guaranteed way to avoid problems.
- Secure your code
Valuable information is stored in databases. Databases are often prime targets for attack because of this fact. Many developers are unaware of the critical vulnerabilities of their code, which is a very scary fact not only for clients, but also for you. Developers can currently be held legally accountable if their own personal negligence leads to a risk of database security that is exploited afterwards.
The solution is often specific to DBMS; that is, it varies from MySQL to Oracle to SQL Server. For example, in PHP with MySQL, it is common to use the function mysql real escape string to escape parameters before sending the SQL query. Alternatively, to “prepare” your queries, you can use prepared statements. Make it your mission to understand the DBMS you work with and the security issues inherent in it.
- Grasp the concept of joins
Single SQL table select statements are easy to write. Business requirements, however, often dictate the need to write more complex queries. “Find all orders for each customer and show the products for each order,” for example. Now, in this particular situation, there would probably be a customer table, a table of orders, and a table of order line (the last one would be to resolve a possible relationship of many to many records). It is readily apparent to those who are slightly more familiar with SQL that a table join will actually require two table joins for this query.
- Know the data types
In SQL, each table column typically has an associated type of data. Typically, text, integer, VarChar, date, and more are types for developers to choose from. If you use indexing, you will probably be perplexed when it should be a simple index scan as to why your query will take forever. This is why developers need to pay particular attention to the types of data and their applications. Due to the increased flexibility granted, non-key attributes that are IDs are often string types as opposed to integers. This is also an area of trouble for junior developers, however, who assume that ID fields are integers.
- Write complaint code
There are standards in all programming languages that web developers should be aware of, and SQL is no different. ANSI and then ISO standardized SQL, occasionally submitting new language revisions. SQL:2008 is the latest revision, although SQL:1999 is the most important revision developers should be aware of. The 1999 revision introduced recursive queries, triggers, PL / SQL and T-SQL support, as well as some new features. It also defined that, contrary to the WHERE clause, the JOIN statements are made in the FROM clause.
- Normalise the data
Standardization of the database is a technique for organizing database content. Database systems can be inaccurate, slow, and inefficient without standardization. The database professional community has developed a series of guidelines for database standardization. Each standardization ‘ level’ is referred to as a form, with a total of 5 forms. First normal form is the lowest standardization level, up to the fifth normal form, which is the highest standardization level.
- Fully qualify the database object names
A fully qualified name for an object is intended to eliminate ambiguity. Beginning developers rarely have access to multiple databases and schemes, making future issues more complicated. When a given user has access to multiple databases, multiple schemes and tables, specifying directly what the user is trying to access becomes crucial.
- Understand indexing
A database index is a data structure that enhances a database table’s operating speed. Indexes can be created using one or more columns of a database table, providing the basis for quick random look-ups as well as efficient access to ordered records. Indexing is incredibly important when working with large tables, however, if they are expected to grow, sometimes smaller tables should be indexed. However, small tables that remain small should not be indexed.
It is important to remember that, as data is added to the table, indexes need to be reconstructed occasionally. Furthermore, while indexes increase the performance of data access, it slows data modification. Because of this, most DBMSes have the option of temporarily disabling an index to facilitate the modification of mass data and then allowing it to be re-enabled and reconstructed later.
- Use the database permissions properly
It is important to handle different database permissions properly while mysql query optimization that has multiple users. Of course, most databases have an administrator user, but does running your queries as an administrator always make sense? Furthermore, would you like to provide your administrator credentials to all your junior developers and users to write their queries? Probably not. Your DBMS depends on the various possible permissions for your database, but common themes exist between them.
- Know the DBS limitations
Databases are powerful tools, but without limitations they are not. Oracle, SQL Server, and MySQL all have unique limitations on things like maximum database sizes, maximum tables, and so on. Without planning or considering the later requirements of their database, many developers unknowingly choose a DBMS solution for their project.