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In this video we'll learn about the CREATE statement as well as shine some light on how datatypes are used in SQLite.
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We know what tables we need,
now it's time to create them.
0:00
But first, a quick disclaimer.
0:03
In this course, we will be using SQLite.
0:06
But SQLite isn't the only
implementation of SQL.
0:09
So if you find yourself using
a different version of SQL,
0:12
just know that things might
look a little different.
0:15
Okay, let's get back to
creating those tables and
0:18
learning about data definition language.
0:21
The first DDL statement we need to
know about is the create statement,
0:23
which is used to create tables.
0:27
If you'd like to follow along,
go ahead and
0:30
click Launch SQL Playground
in the bottom right.
0:32
Let's start by first getting
rid of this comment and
0:36
then creating the concerts table.
0:39
To create a table, you start by typing,
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CREATE TABLE, and
then the name of the table, CONCERTS.
0:44
Then you add parenthesis and inside you
define your columns, separated by commas.
0:52
So let's type ID, DATE, CITY,
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STATE, and VENUE.
1:04
And it looks like DATE is a keyword.
1:09
But that's okay,
it can also be a column name.
1:12
Finally, let's add a semicolon
at the end and hit Run.
1:16
Now, on the left,
we can see a CONCERTS table.
1:22
And if we click on it, we can see it's got
the columns we specified earlier, awesome.
1:26
Getting back to the CREATE statement.
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While this works fine for SQLite, it won't
work so well in other versions of SQL.
1:37
In most SQL implementations,
1:43
when you declare a column, you also need
to specify a data type for that column.
1:45
However, SQLite doesn't
really use data types.
1:50
More on that later.
1:54
But, to see how data types work,
let's pretend that instead of SQLite,
1:56
we're using a different implementation
of SQL, called Microsoft SQL Server.
2:01
To figure out which data types
are available in Microsoft SQL Server,
2:07
let's Google, SQL server data types.
2:11
And let's pick this third result for
technet.microsoft.com.
2:17
Then if we scroll down,
2:22
we can see all the different data
types available in SQL server.
2:24
Let's take a minute to figure out
which types we should use for
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our concerts table,
starting with the ID column.
2:32
Almost always, you'll want your
ID columns to be integers.
2:36
So looking at this list it looks
like we've got a few options,
2:40
bigint, smallint, int, and tinyint.
2:44
And if we click on one,
we can see the different ranges for
2:48
each integer type, and
how much storage space it takes up.
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I think it's safe to say that there
will be less than 32,000 concerts.
2:58
So for ID,
let's pick smallint as the data type.
3:04
Next up is the date column.
3:09
And unsurprisingly, we should use
the date type for the date column.
3:12
Though before we move on,
3:18
lets make sure we know how we
should be representing our dates.
3:19
Different SQL implementations
use different date formats, so
3:23
we want to double check this
before adding any dates.
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Let's click on date, and
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then if we scroll down a bit we
can see the default date format.
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So when we're adding
new data to our table,
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we should use this format for our dates.
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The last three columns on our concerts
table all represent string data
3:44
which is usually represented
by the varchar data type.
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Varchar lets you set a maximum length for
your string, but
3:52
then only uses as much storage
as ends up being required.
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So it's a really good choice for
string data.
4:01
Now that we know what data types we should
use, let's check back in with our query.
4:04
First, let's take a second to reformat
our create statement to have each
4:09
column on a new line.
4:14
Then to add a data type to a column, just
add a space and then add the data type.
4:22
So for our ID,
since we want this to be a small int,
4:28
let's add space SMALLINT, perfect.
4:32
Now let's add in the rest
of those data types.
4:37
Let's add DATE to our DATE column.
4:39
Then for the CITY let's add VARCHAR,
and then for
4:44
the max length lets go with 255 to
make sure we have plenty of room.
4:48
Finally, lets copy that VARCHAR
data type and the space and
4:54
paste it in for
our state and venue columns.
4:58
Great job.
5:04
Now that we've got our data
types lets re-run the query.
5:06
Ooh, looks like we're getting an error
that the Concerts Table already exists.
5:10
Let's find out how to fix
this error in the next video.
5:16
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