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Structured Query Language or SQL is considered the standard language for database management systems used to correspond with a database, either to update on or retrieve data from a database. The SQL is very simple to run and user-efficient, as the commands have a simple syntax. But then, the efficiency of the SQL command is subject to different database functions, specifically in terms of their individual computation time. Also, the efficiency of the language does not mean that optimizing the language would be easier too. Every database requires unique ways to be tuned, according to its individual needs. That is why, using the best SQL database is advisable, as much as knowing different ways to optimize or boost the database, to make sure the best performance out of it. The scope of optimizing SQL Database for developers like say, senior developers differ from the work of a Database Administrator (DBA) in some respect and are alike in other respects. In large companies, developers and DBAs are often required to work together, where, it has been seen that more often than not, a conflict arises between the two teams. There are various ways by which SQL databases can be tuned.
- Proper Indexing
Index is basically a data structure that helps speed up the data retrieval process overall. Unique index is a kind of indexing that creates separate data columns without overlapping each other. Proper indexing ensures quicker access to the database. Excessive indexing or no indexing at all, both are wrong. Without any indexing at all, the processing will be very slow, whereas indexing everything will render the insert and update triggers ineffective.
- Retrieve the relevant data only
Specifying the data one requires, enables precision in retrieval. Using the commands ‘*’ and ‘LIMIT’, instead of ‘SELECT *’ as and when required, is a great way of tuning the database, while avoiding retrieving the whole set of data when the user wants only a certain part of it. Of course, it will not be necessary when the amount of data overall is less. But when accessing data from a large source, specifying the portions required would save a lot of essential time. The ‘*’ command is for use in specifying data from columns, and the ‘LIMIT’ command is when the user requires data from a certain number of rows from among the lot. Selecting sparingly is not exactly a necessary rule, but it does help in avoiding system errors in the future. Also, limiting and specifying the data reduces the further necessity of optimizing of the database to a great deal.
- Getting rid of Correlated Subqueries:
A correlated subquery basically depends on the parent or outer query. This kind of search is done row by row, thus, decreasing the overall speed of the process. This problem usually lies in the command of ‘WHERE’ from the outer query, applying which, the subquery runs for each row, returned by the parent query, consequently slowing the whole process and reducing the efficiency of the database. So, a better way of tuning the database, in this case, is to the ‘INNER JOIN’ command, instead of the correlated subquery. But in certain cases, using correlated subquery is essential.
- Using or Avoiding Temporary Tables according to requirement:
If any code can be well written in a simple way, there is absolutely no need to make it complex with temporary tables. Of course, if a data has a specific procedure to be set up which requires multiple queries, the use of temporary tables in such cases are, in fact, recommended. Temporary tables are often alternated by subqueries, but one has to keep in mind the specific efficiency that each of these would provide in separate cases.
- Avoid Coding Loops:
Avoiding coding loops is very much needed in order to avoid slowing down of the whole sequence. This can be achieved by using the unique ‘UPDATE’ or ‘INSERT’ commands with individual rows, and by ensuring that the command ‘WHERE’ does not update the stored data in case it finds a matching pre-existing data.
- Execution Plans:
The execution plan tool created by the optimizer play major role in tuning SQL databases. They help in creating proper indexes too. Although, its main function is to display graphically the various methods to retrieve data. This, in turn, helps in creating the needed indexes and doing the other required steps to optimize the database.
There are, of course, tons of other ways by which one can tune their SQL database in the most efficient manner. Also, there is big chance that the steps mentioned above, might not be the right choice for all databases. Each database will require optimizing techniques uniquely specific to its needs. There are millions of job opportunities like Senior Java j2ee developers, for instance, which tend to recruit software engineers who would come up with more and more techniques to optimize SQL databases in the best way possible.