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Displaying posts with tag: virtual columns (reset)
Generated (Virtual) Columns in MySQL 5.7 (labs)

About 2 weeks ago Oracle published the MySQL 5.7.7-labs-json version which includes a very interesting feature called “Generated columns” (also know as Virtual or Computed columns). MariaDB has a similar feature as well: Virtual (Computed) Columns.

The idea is very simple: if we store a column

`FlightDate` date

in our table we may want to filter or group by year(FlightDate), month(FlightDate) or even dayofweek(FlightDate). The “brute-force” approach: use the above Date and Time MySQL functions in the query; however it will prevent MySQL from using an index (see below). Generated columns will allow you to declare a “Virtual”, non-stored …

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Working with IP's in MySQL and MariaDB

For MySQL it's a best practice to store IP addresses in a INT column rather than in a VARCHAR. This allows for more compact storage. This best practice is only for MySQL as PostgreSQL does have data types like inet and cidr.

MySQL is equiped with the INET_ATON() and INET_NTOA() functions since version 3.23.15. In MySQL 5.6.3 the INET6_ATON() and INET6_NTOA() functions were addes to finaly add IPv6 address support. To make it easier to work with IPv4 and IPv6 addresses the IS_IPV4_COMPAT(), IS_IPV4_MAPPED(), IS_IPV4() and IS_IPV6() functions were added. The difference between the new and old functions is that the old functions use INT UNSIGNED to store IP addresses and the new function uses VARBINARY(16) for IPv6 addresses and VARBINARY(4) for IPv4 addresses.

Here are some examples about how you could do …

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Virtual columns in MariaDB

Virtual and persistent columns are a feature of MariaDB 5.2+, and HeidiSQL's table editor now fully supports them. Just update your HeidiSQL to the latest build to see this in action.

Also, if you are on a MariaDB server, a brown seal icon in the tree and in the status bar now indicates the right server vendor:

Showing entries 1 to 3