I recently got a request to load hundreds of database tables in a day and a half using csv files our developers created. I considered using SQL Loader but I didn’t want to spend the time understanding the table structure and creating the control file for each table. Another alternative was to use SQL Developer to import the csv files. That goes against my nature because it would be a manual, repetitive and error prone process.
The csv files were fairly small so plain inserts would work. I looked at writing a BASH script to generate the insert statements and it became very complex very quickly. PL/SQL was an option too but I ruled it out because of the requirement to read flat files. I have been using the Python cx-Oracle module recently so I decided to write a Python script for this task.
Python turned out to be the right choice and the script was very easy to write. The only tricky part was recognizing the date fields. Those are unquoted like a numeric field but contain literals like JAN,FEB, etc. Python and cx-Oracle handled everything with a minimum of effort on my part.
Create the csv files in a dedicated subdirectory like : tablename.csv. The first row of each csv file must contain the column names. The script truncates the target table before inserting the csv records. Any double quoted field is considered a literal and unquoted fields are numeric except date fields which must have the format 01-JAN-16.
Use these GitHub links for more information : Readme, Source code
This was a four day course delivered online. The Oracle labs were inaccessible from my work laptop and from my work network so I used my personal laptop from home. This turned out to be a good thing because work interruptions were minimal and I could focus on the class.
The instructor Barry Isaacman has many years of experience with Sun hardware and has done many ZFS Appliance installations. So he had lots of tips on how to set up things optimally. He also provided documents outside the course materials to support further learning. I was really interested in the API and Python integration and he was very helpful.
The labs are excellent and they utilize real ZFS Appliance hardware so performance is pretty good. There is also a ZFS Appliance simulator here.The hardest part was interpreting the class specific instructions for student IP address assignments. After getting the initial settings correct everything worked fine.
I was able to immediately apply my new knowledge as soon as I returned to work this week. We have recently installed ZFS appliances for database backups over Infiniband in two data centers and the installer set up replication between them. I reviewed the configuration and was pleased that the best practices in the class were implemented in the new installation.
I’m just starting to experiment with the API using Python. Here are some links that are promising:
I have been automating and centralizing dba and system administration processes using Python recently. One of the problems I solved was how to create Bash and SQL scripts to run on the remote database servers, copy them to the database servers and then execute them as another Linux account. After I got my Python scripts working perfectly, I discovered that I had re-invented Ansible 🙂
My scripts would have been much less complex and easier to write if I had done them with Ansible in mind. So that’s how I will write them going forward. I also wanted to implement a DBA Data Warehouse so I added cx_Oracle to the mix and used it to store the admin data in a database. I have been using a local virtual machine for Python development and the database was just a local installation on the VM.
Before moving to production I needed to figure out an easy way to get this stuff installed on the production Linux box. Setting it up on my VM was an adventure in Googling and trial and error. So here’s the documentation on how to set it up. You need to define the shell variables first.
wget https://bootstrap.pypa.io/ez_setup.py -O - | python
yum install python-devel
pip install --proxy=https://$my_userid:$my_pasword@$proxy_server:$port cx_Oracle
pip install --proxy=https://$my_userid:$my_pasword@$proxy_server:$port ansible