2. Overview
Objectives
Learn the basics of creating, updating and removing
tables and columns from a database.
Requirements
A database connection
A basic understanding of the types of fields in a
database
Estimated Time
8 minutes
3. What about tables and columns?
If you are using this Framework, the possibility is very
high that you are using some sort of database. With that
database you will need to create, update and remove
table and columns.
By the end of this tutorial, hopefully you have the basics
of creating and table columns. And because ProdigyView
is database agnostic, there will work for any database that
ProdigyView supports.
4. Defining Columns
Before we make a table, we have to define columns. Columns are be defined in
the format of an array where the key is the column name and the value is an array
of attributes that define that column.
The attributes that can be used to define a column are as follows:
Auto_increment: A boolean that defines this column as a value that will be
auto incrementing
Unique: A boolean that defines if this column is unique.
Type: The attribute with the most options, the type defines what kind of
column is being created. Text, varchar, timestamp, boolean, etc.
Precision: How precise the column is. So for example if you only want a
varchar to be 20 characters, this would be set to 20.
Default: The default value for the column.
Hopefully that gives you an idea of where we headed with this example. Lets look
at a code sample next.
5. Defined Columns Example
Store in array Auto incrementing defined Precision is being defined
Set a type Set a default value
6. Creating a Table
Ok so we have our columns defined. Lets move onto
creating a table with the columns. In our example below,
we set the primary keys to be the ‘id ‘handle ‘handle’
column and we are passing in the table name and the
columns from previous slide.
1. Checks if the table exist
2. Set table name 3. Set columns 4. Set primary Keys
7. Adding More Columns
Let’s say we forgot columns because we were distracted
by celebrity marriage that only lasted some 70 odd days
and need to add some more columns. Not problem. You
simply have to know the name of the table you are
appending the column too, the name of the column you
want to append, and the attributes that define that
column.
1. Define columns 2. Iterate through columns
3. Add the
columns
individually
8. Removing A Column
Oh wait, another mistake. Now you need to remove a
column. Not a problem either. Simply pass in the table
name and column name to dropColumn and the column
with be removed.
1. Check if the column exist
2. The name of the table 3. The name of the column
9. Dropping A Table
So the whole idea behind your table was a flop. Let’s get
rid of the whole thing. Drop the table
1. Check if table exist
2. Drop/Delete the table
10. Challenge!
Below is an optional challenge to help you better understand
tables and columns in ProdigyView.
1. Create an table that has columns for an auto-incrementing
id, email address and column that holds the date
registered.
2. Make the email column unique.
3. Insert an email address into the that column. Then try to
enter the same email again.
4. Add a Boolean column for if the user is active, set to false.
5. *Add a password column that has a default value that
generates a random string.
11. The Note So Obvious
1. Checking if a table exist can be checked with
PVDatabase::tableExist() method.
2. Checing if a column exist can be checked with
PVDatabase::columnExist() method.
3. You can clear/truncate a table with
PVDatabase::clearTableData() method.
12. Review
1. Create a table using the PVDatabase::createTable()
method.
2. Add a column using the PVDatabase::addColumn
method.
3. Remove a column using
PVDatabase::removeColumn() method.
4. Drop a table using the PVDatabase::dropTable()
method.
13. API Reference
For a better understanding of the database, visit the api
by clicking on the link below.
PVDatabase
More Tutorials
For more tutorials, please visit:
http://www.prodigyview.com/tutorials
www.prodigyview.com