Fminer modify table data how to#
Fminer modify table data update#

Let's say one of the companies that our participants work for got bought out and the name has changed Fisher LLC is now Megacorp Incorporated. Because we have a where clause that we can use to make updates, we can make changes to more than one record at a time if we want to. So we need to be as specific as possible with our statement and check our logic first, before changing data in the database.

Here in DB Browser, we have one, but in the real world, we won't. And when working with most databases, there's often no undo feature. And if I left it off, I'd set the last name to Morrison for every record in the table. The where clause here is important because it targets only the correct record. Run that, and I can see the change has been made. Then I'll select my previous query to take a look at Carlos's record. I'll select this and then I'll run the query.

Fminer modify table data update#

I'll write, update people, set last name equals Morrison, spelled correctly, where ID number equals 175. Once we've checked that, let's finally write the update statement that will make this change. So using SQL, we can first write a select statement to check that we're working with a record that we intend to. So we can use that to be absolutely certain we have the right participant record. The people table has a unique number for each participant, and that's something you'll find is the case in many databases, which deal with people's information. But there's an even better way to approach this. We'd write an update statement that uses both the first name and city as conditions to update the last name this way. Writing a select statement with more information confirms that this one participant is named Carlos and is from Houston. A better way to update this record is to match more information by adding other fields that identify this particular participant. And you can confirm that by running a select on records with the last name Morrrison. I know that we'll work with this dataset. Because we know that Carlos's last name was misspelled, we can find that misspelling and replace the value like this. So we need to be more specific about which record to update. Uh oh, it looks like we have a lot of Carloses. To do that, I'll translate the condition this would match into a select statement instead.

Is Carlos Morrison, the only Carlos in our table? It's best to check.

But before I run that, we need to pause a moment. I'll write an update statement to change the last name to Morrison, spelled correctly, for the first name, Carlos. Since Carlos has already taken our quiz and already provided other information, it's best to just go in and change the last name field rather than delete Carlos and add a new, correct record. Carlos Morrison of Houston, Texas accidentally typed too many Rs. Let's say we were contacted by one of our participants who noticed they had entered their name incorrectly. If you leave off a where clause, the change will apply to all the records in the whole table.

Fminer modify table data how to#

To update information, we have to tell the database which table we're using, what fields to update with what values, and optionally, a where clause to specify how to find records to update. Update is useful where we want to change information that's already there, rather than adding new records with different information. Data in the database can be modified using the update keyword.