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Populating a MySQL database

From: PHP with MySQL Essential Training

Video: Populating a MySQL database

In the previous movie, we learned the syntax that we use to create, read, update and delete records in MySQL. Now let's start adding data to our subjects table and take our new MySQL commands out for a test drive. So as you can see I'm already inside MySQL and I've already got my database created and my subject's table created. And those are the columns there, it says field. Those are the columns that I've got to work with. Let's try some of the SQL that we just learned. So let's start by doing select and then asterisk from subjects. That's the simplest command that we can do for a read.

Populating a MySQL database

In the previous movie, we learned the syntax that we use to create, read, update and delete records in MySQL. Now let's start adding data to our subjects table and take our new MySQL commands out for a test drive. So as you can see I'm already inside MySQL and I've already got my database created and my subject's table created. And those are the columns there, it says field. Those are the columns that I've got to work with. Let's try some of the SQL that we just learned. So let's start by doing select and then asterisk from subjects. That's the simplest command that we can do for a read.

And it comes back and says there's nothing there. I don't get anything back there are no rows inside the subjects table. We have to add one. So let's try that with insert, sert into. And then our subjects. And then you'll remember that in parentheses we're going to provide the columns that we want to insert into. Now, I'm going to leave the ID column off. Remember it's going to auto increment that for us. So I don't need to value. I could. I could go ahead and tell it exactly what ID I wanted it to have. But it's better I think most times with that ID to let my SQL be in charge of it.

So, instead, I'm just going to skip straight to the menu name and then position and visible. Now I could keep typing here or I could just hit return and because I haven't hit a semicolon yet, mysql is waiting for the rest of the command. So values and then the values that I want for each one. So for menu name, I'm going to call this first one about Widget Corp. Now notice that I'm using single quotes around that. You want to use single quotes always in MySQL. Not double quotes. Single quotes. That's just the way that MySQL works. And then for the position we're going to have the number one. That could be in single quotes but because it's an integer I don't have to. So it's going to be in position one, and visible is a Boolean, and that's going to be true or false.

Now you could actually type TRUE all capitals or FALSE all capitals but those are just constants in mysql that reference either 0 or 1. So, if we want it to be visible, we just type a 1. If we don't, a 0. Most people, you just use 1 and 0 instead of true and false. And then a semicolon at the end to let it know that I'm done. And I'll hit return. You'll notice that it says query okay. One row affected. So there it is. It tells me that it changed one row. That it did something to one row. It'll always give you that status update to let you know how many rows were changed in the process.

Now let's try our statement from before. We can hit the up arrow, to go back to the Select all from subjects. Hit Return and you'll see that we get a nice table rendered back to us that shows all of the columns and the data that's in each one of those. And at the bottom it tells us one row in the set. Alright, so lets try adding in another one. For this one let's do insert into subjects again and I'm going to use my up arrow to back and find the one that I did previously. You'll see that now it's unwrapped it, so it's all in one line, that's fine and I'm going to keep the beginning part the same, I'm just going to change the values here.

I'll use my arrow to go back and instead of About Widget Corp, I'm going to call this one Products. It's position will be 2 and it will also be visible so it'll be a 1. And I'll just hit Return from anywhere on the line and it made that change. You can use the Up arrow to go back, and see now we have two of them. ID 1, and ID 2, position 1, and position 2. See how that works? Let's add a third one. We'll hit the Up arrow. And this one instead of products we'll make it services. I don't think we need to take a look at that one, but you can. I'm going to hit the up arrow again and I'm just going to add a fourth one real quick.

I'm going to call this one miscellaneous. I'm going to make it number 4 but I'm going to make it not visible. And now let's take a look at all of them. That's what they all look like, that's what I have in my database. All of them are marked visible except for this last one. It's marked not visible with the idea that that would not show to the public. It would not be in our navigation menu for them to select from. Now that we have one that's not visible, let's try a variation on this select. We say where visible equals one. Now I get back just the visible ones or where visible equals zero, I get back the ones that are not visible.

So, my conditions now are affecting the set of data that I get back. In addition to where we can have order by and we can sort them by position ascending. There we go. Returns the position ascending. If we go back and do position DESC, it would be descending position 3, 2, 1. See how they reversed? And of course we could have instead of by position, we could sort them by menu name. Now they'll be in alphabetical order. Now in all of these cases, we're expecting that it's going to give us back one or more rows.

Maybe only one row matches like when we ask for the ones that are not visible. Or maybe many rows match, like when we ask for the ones that are visible. But typically if we want to just get a single row back, then to do that we're going to say find the one from subjects were ID equals 2. We're going to specify the ID. In that case we know that we're only going to get one back or nothing back. They couldn't find it that ID didn't exist. We'll get nothing. But if it does exist we'll get one back. We'll never get two or three or four or anything else like that because only one thing can have this ID. It's an unique identifier.

Last of all let's just try specifying some of the columns we want. I'm going to go back to one of these earlier ones. And let's specify columns. Instead of saying that we want to have all of them with the asterisk, let's say we'd like to just see the menu name comma position. Hit Return and you'll see that it just returns columns for menu name and position, the other ones are just left off. So for any column that we wanted to include, we just specify it right after the select statement. Okay, and so we've done some playing with the read statements. Let's try and update now. So let's say that we want to update our subjects and I'm going to hit Return.

Again, it's waiting for me to put a semicolon, set, I'm going to set visible equal to 1 and hit Return again where ID equals 4. That's going to take that fourth item which is not visible and make it visable select all from subjects. Now you can see it changed it, it went from being not visible to being visible we updated it. Now let me just show you what happens if we say update subjects set visible equal to 0 we don't specify the ID. It's going to change it to all rows.

It says here rows matched 4. 4 rows affected. Take a look at this. You can see that they're all not visible now. It's very important to decide whether you're just changing one row in which case we need that ID to be specified. Or for it to be changing all rows. And we don't have to just have one row, we can actually use our where statement a little more creatively. We can say, set all of them to visible where id is less than 4. So we'll get the first three, there we are. Three rows changed, you can see that I changed these three.

So my where statement said everything with id less than, it matched these three and so that's what it updated. It updated for all of those at the same time, not the 4th one. And then now that we've worked with create, read and update, the last one is delete. So let's do delete from subjects where ID equals 4. And we'll just get rid of that last one there. One row affected. And we go back and look and sure enough, now it's gone. So no we've been able to successfully use our create, read, update and delete commands in MySQL to make changes to our subject's table. Feel free to go ahead and play around with it a little more, you can make other edits, updates, deletes, get comfortable with it. And when you're ready let's go to the next movie where we can talk about relational database tables.

Show transcript

This video is part of

Image for PHP with MySQL Essential Training
PHP with MySQL Essential Training

131 video lessons · 31642 viewers

Kevin Skoglund
Author

 
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  1. 4m 8s
    1. Welcome
      1m 0s
    2. Using the exercise files
      3m 8s
  2. 15m 6s
    1. What is PHP?
      3m 52s
    2. The history of PHP
      2m 51s
    3. Why choose PHP?
      4m 10s
    4. Installation overview
      4m 13s
  3. 54m 53s
    1. Overview
      2m 33s
    2. Working with Apache Web Server
      6m 56s
    3. Changing the document root
      7m 24s
    4. Enabling PHP
      6m 16s
    5. Upgrading PHP
      3m 30s
    6. Configuring PHP
      10m 3s
    7. Installing MySQL
      5m 46s
    8. Configuring MySQL
      7m 24s
    9. Text editor
      5m 1s
  4. 31m 25s
    1. Overview
      3m 27s
    2. Installing WampServer
      5m 46s
    3. Finding the document root
      2m 24s
    4. Configuring PHP
      8m 12s
    5. Configuring MySQL
      5m 45s
    6. Text editor
      5m 51s
  5. 19m 12s
    1. Embedding PHP code on a page
      6m 43s
    2. Outputting dynamic text
      5m 55s
    3. The operational trail
      2m 27s
    4. Inserting code comments
      4m 7s
  6. 1h 18m
    1. Variables
      7m 50s
    2. Strings
      4m 38s
    3. String functions
      8m 54s
    4. Numbers part one: Integers
      6m 27s
    5. Numbers part two: Floating points
      5m 25s
    6. Arrays
      10m 0s
    7. Associative arrays
      6m 37s
    8. Array functions
      6m 33s
    9. Booleans
      3m 50s
    10. NULL and empty
      5m 15s
    11. Type juggling and casting
      8m 27s
    12. Constants
      4m 43s
  7. 27m 37s
    1. If statements
      6m 0s
    2. Else and elseif statements
      4m 16s
    3. Logical operators
      7m 30s
    4. Switch statements
      9m 51s
  8. 42m 15s
    1. While loops
      8m 41s
    2. For loops
      5m 59s
    3. Foreach loops
      8m 16s
    4. Continue
      8m 28s
    5. Break
      4m 8s
    6. Understanding array pointers
      6m 43s
  9. 37m 25s
    1. Defining functions
      8m 25s
    2. Function arguments
      5m 32s
    3. Returning values from a function
      7m 33s
    4. Multiple return values
      4m 53s
    5. Scope and global variables
      6m 2s
    6. Setting default argument values
      5m 0s
  10. 20m 18s
    1. Common problems
      3m 47s
    2. Warnings and errors
      8m 36s
    3. Debugging and troubleshooting
      7m 55s
  11. 57m 57s
    1. Links and URLs
      5m 33s
    2. Using GET values
      5m 35s
    3. Encoding GET values
      8m 41s
    4. Encoding for HTML
      9m 26s
    5. Including and requiring files
      7m 40s
    6. Modifying headers
      6m 45s
    7. Page redirection
      6m 43s
    8. Output buffering
      7m 34s
  12. 1h 3m
    1. Building forms
      7m 28s
    2. Detecting form submissions
      5m 59s
    3. Single-page form processing
      7m 57s
    4. Validating form values
      10m 40s
    5. Problems with validation logic
      9m 54s
    6. Displaying validation errors
      7m 23s
    7. Custom validation functions
      6m 28s
    8. Single-page form with validations
      7m 25s
  13. 28m 5s
    1. Working with cookies
      2m 49s
    2. Setting cookie values
      5m 55s
    3. Reading cookie values
      6m 1s
    4. Unsetting cookie values
      4m 51s
    5. Working with sessions
      8m 29s
  14. 48m 39s
    1. MySQL introduction
      6m 43s
    2. Creating a database
      7m 41s
    3. Creating a database table
      7m 42s
    4. CRUD in MySQL
      5m 48s
    5. Populating a MySQL database
      7m 32s
    6. Relational database tables
      6m 40s
    7. Populating the relational table
      6m 33s
  15. 56m 4s
    1. Database APIs in PHP
      4m 51s
    2. Connecting to MySQL with PHP
      7m 45s
    3. Retrieving data from MySQL
      8m 47s
    4. Working with retrieved data
      6m 12s
    5. Creating records with PHP
      6m 58s
    6. Updating and deleting records with PHP
      9m 6s
    7. SQL injection
      3m 5s
    8. Escaping strings for MySQL
      6m 45s
    9. Introducing prepared statements
      2m 35s
  16. 35m 58s
    1. Blueprinting the application
      7m 19s
    2. Building the CMS database
      5m 14s
    3. Establishing your work area
      4m 38s
    4. Creating and styling the first page
      4m 22s
    5. Making page assets reusable
      6m 36s
    6. Connecting the application to the database
      7m 49s
  17. 32m 49s
    1. Adding pages to the navigation subjects
      5m 58s
    2. Refactoring the navigation
      6m 7s
    3. Selecting pages from the navigation
      6m 2s
    4. Highlighting the current page
      5m 26s
    5. Moving the navigation to a function
      9m 16s
  18. 1h 45m
    1. Finding a subject in the database
      9m 48s
    2. Refactoring the page selection
      10m 52s
    3. Creating a new subject form
      6m 55s
    4. Processing form values and adding subjects
      11m 20s
    5. Passing data in the session
      9m 16s
    6. Validating form values
      9m 40s
    7. Creating an edit subject form
      8m 30s
    8. Using single-page submission
      7m 44s
    9. Deleting a subject
      9m 44s
    10. Cleaning up
      10m 37s
    11. Assignment: Pages CRUD
      4m 30s
    12. Assignment results: Pages CRUD
      6m 10s
  19. 39m 26s
    1. The public appearance
      8m 52s
    2. Using a context for conditional code
      11m 37s
    3. Adding a default subject behavior
      6m 9s
    4. The public content area
      5m 51s
    5. Protecting page visibility
      6m 57s
  20. 1h 3m
    1. User authentication overview
      4m 3s
    2. Admin CRUD
      8m 41s
    3. Encrypting passwords
      7m 26s
    4. Salting passwords
      5m 42s
    5. Adding password encryption to CMS
      11m 54s
    6. New PHP password functions
      3m 13s
    7. Creating a login system
      11m 28s
    8. Checking for authorization
      5m 48s
    9. Creating a logout page
      5m 40s
  21. 2m 4s
    1. Next steps
      2m 4s

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