Posts tagged SQL

Table size in PostgreSQL

Disk space seems endless, until you run out and/or have to pay the bill. The question is how to find tables with a high disk storage usage and with the query below it shows the table and index size, but also the size of TOAST data for PostgreSQL.

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Renaming database in PostgreSQL

Sometimes you have a system with legacy naming standards, but you really want to switch over to the new standard to keep all the scripting clean without some exceptions no one is going to remember in 12 months. Oracle had the command ALTER DATABASE, but since Oracle 10 you need to take the database offline and do some magic. MySQL got the RENAME DATABASE option with release 5.1.7 and lost the option again with release 5.1.23 as it was eating data.

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Starting to stop SQL-injections, part 2

In a previous posting, I gave an example of how to make database queries safer by using parameter binding and basically stopping SQL-injections. The next step is to make the code more readable and maintainable. This doesn’t sound like a priority for secure software development, but readable code is also code that can be verified and maintained by other people. It gives you the edge to debug problems quickly and invites others to supply patches. So let take the example where the previous posting ended.

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Starting to stop SQL-injections

In a lot of PHP-examples strings are concatenated before a database query is being executed as below. Some examples advise to use PHP-functions mysql_real_escape_string() and/or addslashes() to make database query safe against SQL-injections. But this isn’t really a solution as when using addslashes() also requires the use of stripslashes() after retrieving data from a database. Some sites show the lack of proper implementation and show the famous string on a website.

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