April 1999
Intermediate to advanced
552 pages
15h 39m
English
Content preview from Oracle Distributed Systems
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.
Column Groups and Priority Groups
Column groups and priority groups provide interfaces to a variety of built-in conflict resolution techniques and the easiest way to configure your application to resolve conflicts automatically. Let’s look at them one at a time.
Column Groups
A column group is a set of one or more columns associated with a single conflict resolution method. A column cannot belong to more than one column group, and columns that are not explicitly assigned to a column group are members of a shadow column group, which Oracle creates by default and which uses the default conflict resolution methods.
For example, suppose that you want to define a column group for the EMPLOYEES table described in the following table:
Column Name | Type |
|---|---|
EMPLOYEE_ID | NUMBER(10) |
LAST_NAME | VARCHAR2(30) |
FIRST_NAME | VARCHAR2(20) |
SOCIAL_SECURITY_NO | VARCHAR2(11) |
MARITAL_STATUS | VARCHAR2(1) |
HOME_PHONE | VARCHAR2(12) |
PERS_GLOBAL_NAME | VARCHAR2(30) |
PERS_TIMESTAMP | DATE |
MANAGER | NUMBER(3) |
DEPT | NUMBER(3) |
SAL_GRADE | NUMBER(3) |
SENIORITY | VARCHAR2(10) |
PAYROLL_GLOBAL_NAME | VARCHAR2(30) |
PAYROLL_TIMESTAMP | DATE |
Use the procedure DBMS_REPCAT.MAKE_COLUMN_GROUP to define a column group for fields that the personnel site maintains (i.e., LAST_NAME, FIRST_NAME, SOCIAL_SECURITY_NO, MARITAL_STATUS, HOME_PHONE). The application records information about changes to these fields in PERS_GLOBAL_NAME and PERS_TIMESTAMP.
EXECUTE dbms_repcat.make_column_group( - gname => 'HR', - oname => 'EMPLOYEES', - column_group => 'CG_EMP_PERSONNEL', - list_of_column_names => ...
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.
Read now
Unlock full access
More than 5,000 organizations count on O’Reilly
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.