PHP-and-MySQL/C3/MySQL-Part-5/English-timed
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Revision as of 17:12, 29 May 2015 by Sandhya.np14 (Talk | contribs)
Time | Narration |
00:01 | Welcome to mySQL part 5. To echo our data to the user and to display the results from this, we'll need to use while statement. |
00:12 | As I mentioned, we have created a $row variable and this is "= mysql_fetch_assoc". |
00:21 | This is creating an associative array from our "extract" query which is here. |
00:27 | So, we are selecting everything in the "people" table and ordering them by "id" in ascending order. |
00:33 | Inside our while, since we wrote $row as an array and it's an associative array, row[0] will be wrong because these are numeric. |
00:46 | These are numeric id tags and instead of this we'll use our field names, since this is associative. |
00:59 | So, instead of 0, 1, 2, 3, 4 we'll be using the actual name. |
01:05 | Let's create variables from this. Let me say $id and then $firstname equals, we are using the same structure throughout. |
01:15 | So, it's quite easy to copy and paste this. |
01:19 | Let's indent this. |
01:24 | So we have 5 altogether. |
01:28 | So that's five and then let's just change. This is a lazy act! |
01:34 | But it's just a lot quicker to do this way. |
01:38 | So $lastname and we have the date of birth ($dob). We also have the $gender. |
01:47 | We have all our data and now how do we use this? |
01:51 | We need to use the echo command. |
01:55 | There might be a loop inside the middle, at the moment. So, anything we echo out will be repeated. |
02:02 | Every record we say and that's right too. We'll repeat this code. |
02:07 | For example, I say "Text" here. There are currently 4 records. |
02:13 | After refreshing this page, you should see Text echoed out 4 times. |
02:18 | By typing out 4 times, this piece of code here, represents every loop. |
02:24 | Therefore we can incorporate for example, $id or $firstname or any other, that we have extracted from the database using our associative array. |
02:36 | Now I'll write: $firstname $lastname was born on $dob for date of birth and is and I'll put $gender up there. |
02:49 | Not forgetting our line-break. I'll refresh our page. |
02:54 | Then we have our set of data structured using the variable names. |
02:59 | We have given in the correct order and also it has been repeated through for every record we have. |
03:08 | Okay, we have just given out the content of our table using this star, declared by this asterisk, where it collects every single data on every record. |
03:22 | Now let me do this. I'll say if $gender== "F" then $gender= "Female" . |
03:39 | The actual spelling of that and then let us say else $gender= "Male". This is just rewriting the variable depending on the value. |
03:50 | If we refresh now, we can see this has changed to male Male and female Female. We also have some interesting ways of displaying this data. |
04:00 | At the moment, I'm selecting from the people table and ordering by id and ascending order. |
04:07 | I can also order by descending id. You can see that this switches this data around. |
04:15 | We can also order it by firstname. This will put this in descending alphabetical order and ascending will put this in ascending alphabetical order. |
04:33 | So, we got A, D, E, and K. |
04:36 | You can do the same with the surname. |
04:39 | You could do the same with anything. Even date of birth, as long as you include this over here. |
04:46 | Another thing to do is, let me just take this back to id and have this as descending. We can use this LIMIT 1 or we can say LIMIT 2, 3 or 4. |
04:58 | Now I'll LIMIT 1 for the purpose of this. |
05:00 | Now let's have 1 to let the user of the page know the last person that was inserted into this table. |
05:11 | So I say echo here. |
05:16 | echo "Last person to be inserted into table was..." and I'll leave it like that and add a line-break. |
05:27 | I'll just echo out the first and last name. Ok. |
05:33 | So, here we can see that there is a lot of confusion. |
05:38 | "Last person to be inserted.." Yes, in fact it does work! |
05:43 | It is already typed in the "LIMIT" command. |
05:46 | What I've done is by limiting this by 1 in descending order of id - the id is incremental - I get 4 at the top and if we are limiting this by 1, 4 will be the only record that is selected. |
06:01 | Therefore, the last person in the table, as per the last record displayed, will have its value echoed out. |
06:09 | This while will only return 1 data value. |
06:13 | Since we are returning 1 data value here, we are confused by these. |
06:18 | This is one command here, SELECT asterisk (*) FROM "people" , ORDER BY id DESC is another and LIMIT 1 is yet another. |
06:27 | We don't use commas or anything. This is just how we write our code inside our query. |
06:34 | Okay, just to test this- I'll insert just using the Insert function in php MyAdmin and I'll insert another record. |
06:45 | For example, let's type in "David Green" and our date of birth could be random. |
06:55 | It doesn't really matter what we type in here. We say Male. |
07:00 | I came down here and submit this data. |
07:02 | Click on Browse and we have a new value here. |
07:06 | When we come back here and refresh, that will change to "David Green". |
07:10 | So, this is really useful if you have a website in which you are putting videos or personal pictures. |
07:17 | You can just place in the last thing the user had inserted. |
07:21 | Or may be the last person that has been registered on your website or anything. |
07:30 | Possibility of using this is endless. |
07:33 | Basically how to echo out data and how to manipulate it by just using mysql query. |
07:44 | In the next part, we will allow our user to specify which data they want to show. |
07:50 | We will create some html forms to enable them to do this. |
07:55 | This will let them select a name from the database or table of their choice. |
08:00 | So, join me in the next part. |
08:01 | Bye for now. This is Juanita Jayakar, dubbing for the Spoken Tutorial Project |