Querying Oracle Nested Tables

Nested tables are one method you can use in Oracle to store a one-to-many relationship. You essentially put a table inside of another table. The nested table is actually stored separately and is linked to the original table by the unique row id. Working with this kind of table and the data within is different. … Continue reading Querying Oracle Nested Tables

EDGE Training Method

EDGE is a basic teaching tool designed to guide the instructor in a series of steps that will include all learning styles. This is the training method taught by the Boy Scouts of America. Since attending the class, I have used this method for all the training materials I create. The EDGE Method The steps … Continue reading EDGE Training Method

Full Outer Joins

When you want to see a list of all values from two tables in a join, even if there are no matches, you want the Full Outer join. It fills in nulls on both sides where needed. Try this query: SELECT * FROM hr.regions FULL OUTER JOIN hr.countries USING (region_id); If you look through the … Continue reading Full Outer Joins

Using IN, ANY, and ALL Queries

ANY and ALL queries are related to IN queries in that they are used for multi-row returns. They also allow comparisons to be made (equal, not equal, greater than, less than, etc.). The IN Condition Reviewing an IN condition in a query first, we know that the field on the left side of the IN … Continue reading Using IN, ANY, and ALL Queries

Order of SQL SELECT Clause Evaluation

SQL Clauses are evaluated in the following order: Find Where Good Snakes Have Oaths FROM clause WHERE clause GROUP BY clause SELECT clause HAVING clause ORDER BY clause

Java Programmer 1 Exam Topics

1Z0-808 - DevCert: Java SE 8 Programmer Java Basics Define the scope of variables Define the structure of a Java class Create executable Java applications with a main method; run a Java program from the command line; including console output. Import other Java packages to make them accessible in your code Compare and contrast the … Continue reading Java Programmer 1 Exam Topics

Linux Echo and Reading Files

Assigning values to variables, using ECHO and reading a file. Assigning Variables Name the variable on the left. Variables names are case sensitive. No spaces around the equals sign in the middle. The value is on the right side of the equals sign. When using the variable afterwards, precede the variable name with a $. … Continue reading Linux Echo and Reading Files

Run an Unattended SQL Script from Linux using nohup

Some scripts take a long time to run. If they are interrupted, you will lose all your work. To get around that, create a bash file to run the script for you, then run the script file with the NOHUP option so it won't hang up. Scripts and Running with NOHUP Make sure you have access … Continue reading Run an Unattended SQL Script from Linux using nohup

Using Oracle’s srvctl to Complete a RAC Flashback

A flashback restore point is handy for deployments of new code and testing. Remember: You cannot properly shutdown a RAC database using sqlplus command. Use srvctl commands instead. Flashback to Restore Point (RAC) >$ srvctl stop database -d myDB -o immediate >$ srvctl start instance -d myDB -i myDB1 -o mount SQL> flashback database to restore … Continue reading Using Oracle’s srvctl to Complete a RAC Flashback

Oracle Single Row Character Functions Returning Numeric Values

Exam Topic: Using Single-Row Functions to Customize Output - Describe various types of functions available in SQL Single row functions return a result for every row in a result. They can be used in any part of a SQL query, such as the SELECT lists or any part that can use a conditional statement. Oracle 11g has … Continue reading Oracle Single Row Character Functions Returning Numeric Values