While I try to keep things simple, sometimes eliminating options and explanations comes back to haunt me. After posting how to open a Fedora firewall port for a LAMP stack, somebody got trapped by my instructions for installing MySQL on Fedora. They got stuck because they had the following setting in their
I’d suggested using that
bind-address value for a DHCP VMware Fedora installation in Step #7. I was trying (more...)
After installing the LAMP stack on Fedora, you need to open port 80 in the Firewall to access the PHP programs on the Fedora instance from external servers. You can open a firewall port by launching the firewall-config application as the
root user with the following syntax:
The firewall-config utility opens the following dialog message:
Click on the Ports tab, and you’ll see the following:
Click on Add button to add a port (more...)
My students wanted an extra credit assignment, so I thought a LAMP configuration and test would be appropriate. The only problem was I hadn’t added it to their course VMware instance. So, here are the instructions to install Apache2, PHP, and MySQLi for a complete LAMP stack.
The post builds on my Fedora Install of MySQL and MySQL Workbench on Fedora posts from last year. It also presumes that you’ve installed a studentdb database but (more...)
A student posed the question about why table names are case sensitive. That’s because case insensitive table names are the default installation, as qualified in the MySQL documentation. You can verify that with the following query:
WHEN @@lower_case_table_names = 1 THEN
'Case insensitive tables'
'Case sensitive tables.'
END AS "Table Name Status";
The default value returned is:
| Table Name Status |
| Case sensitive tables. |
PostgreSQL like Oracle supports record data types but unlike Oracle, PostgreSQL doesn’t support collections of record data types. Here’s an example of how to define a PostgreSQL composite data type, and how to use it as a column’s data type.
CREATE TYPE address_type AS
( street_address VARCHAR
, city VARCHAR
, state VARCHAR
, zip_code VARCHAR );
Then, you define an ADDRESS table, like:
CREATE TABLE address
( address_id SERIAL
, address_struct ADDRESS_TYPE ) (more...)
PostgreSQL’s approach to automatic numbering, is simpler than Oracle, MySQL, and Microsoft SQL Server. For example, you have a two-step process with Oracle, MySQL, and Microsoft SQL Server. First, you create an Oracle table with the
GENERATED AS IDENTITY clause, a MySQL table with the
AUTO_INCREMENT clause, and a Microsoft SQL Server table with the
IDENTITY(1,1) clause. Then, you need to write an
INSERT statement like:
INSERT statement excludes the auto-incrementing column from the (more...)
I replaced my OtterBox Defender with an i-Blazon Prime case when upgrading to the iPhone 6. It appeared a good option, and for 4 months it was fine. Yesterday, the latch broke and my iPhone fell to the ground as a walked. Fortunately, my iPhone landed flat, the i-Blazon plastic case absorbed the impact, and my iPhone was undamaged.
Here’s a photograph of the damaged case:
While I wanted to order only the belt portion (more...)
I promised my students an example of writing xquery statements in Microsoft SQL Server. This post builds on two earlier posts. The first qualifies how to build a
marvel table with source data, and the second qualifies how you can create an XML Schema Collection and insert relational data into an XML structure.
You can query a sequence with xquery as follows:
DECLARE @x xml;
SET @x = N'';
SELECT @x.query( (more...)
Working through Chapter 7 of the Querying Microsoft SQL Server 2012 book for Microsoft’s Exam 70-461, I found the XML examples incomplete for my students. I decided to put together a post on how to create:
- An XML Schema Collection type.
- A table that uses an XML Schema Collection as a column’s data type.
- An example on how you can transfer the contents of a table into the XML Schema Collection.
This post assumes you (more...)
My students asked if you could embed an
OFFSET x ROWS FETCH NEXT y ROWS ONLY clause in a SQL Server T-SQL user-defined function. The answer is no, it isn’t Oracle (yes, you can do that in Oracle Database 12c with an NDS statement). There’s an example in Chapter 2 of my Oracle Database 12c PL/SQL Programming book if you’re interested. I also demonstrate a different approach to SQL Server T-SQL table functions in (more...)