SQLite ABS() Explained

In SQLite, ABS() is a built-in scalar function that returns the absolute value of its argument.

The absolute value is the non-negative equivalent of the argument. It can be thought of as the distance from zero that the number resides on the number line, without considering direction.

Read more

Fix Msg 3728 in SQL Server “… is not a constraint”

If you’re getting an error that reads something like “Msg 3728, Level 16, State 1, Line 1
‘DF__Dogs__DogId__6FE99F9F’ is not a constraint
“, it’s probably because you’re trying to drop a constraint that isn’t in the database.

To fix this issue, check to make sure the constraint exists before dropping it. Alternatively, use the IF EXISTS clause to drop the constraint only if it exists.

Read more

MySQL VERSION() Explained

In MySQL, VERSION() is a built-in function that returns the MySQL server version.

The result is a string that uses the utf8mb3 character set. A suffix may also be appended to the version number indicating server build or configuration information.

Read more

How to Create a Repeating Sequence in SQL Server

When we create a sequence object in SQL Server, we have the option of making it a repeating sequence or a nonrepeating sequence. By repeating I mean, we can have the sequence continually start again once the min/max value has been reached. In other words, we can have the sequence reiterate over and over again.

We can do this with the CYCLE argument.

Read more

Fix “WRONGTYPE Operation against a key holding the wrong kind of value” when Setting a Hash in Redis

If you get an error that reads “WRONGTYPE Operation against a key holding the wrong kind of value” when setting a hash with a command like HSET or HSETNX, it’s probably because you’re trying to set a non-hash key that already exists. In other words, the key already exists, but it doesn’t contain a hash.

To fix this issue, be sure to use these commands on keys that either don’t already exist, or contain a hash.

Read more