# Chapter 1
Outline

This chapter outlines the Empress Replication User's Guide Manual. This manual is explained in the following chapters:

1. Outline
     This chapter outlines the Empress Replication User's Guide Manual.

2. Introduction
     This chapter introduces Empress Replication concepts. Examples for potential usage of Empress Replication are given at the end of the chapter.

3. Empress Replication Scenarios
     This chapter introduces Empress Replication by examples. The examples are given through different scenarios that imaginary company XYZ encounters when distributing information to its divisions and branches. The purpose of each scenario is to show different situations in which Empress Replication can be used.

4. Empress Replication Details
     This chapter is a detailed explanation of Empress Replication concepts and their usage. The general usage of SQL commands and utilities that are related to Empress Replication are explained to clarify the concepts. Empress Replication Details are explained through these main sections:
   - Introduction
   Gives an introduction to the contents of the chapter.
   - Replication Tables
   Gives definition for Master Table and Replicate Table, their special features, and their restrictions. Introduces Original Master and Master Table Switch concepts.
   - Replication Relation
   Introduces Replication Relation between a Replication Master Table (RMT) and a Replication Replicate Table (RRT). Its relevant concepts such as RMT-Side and RRT-Side, Replication World, Replication Replicate Entry and Replication Master Entry, and Replication Master Order are also described.
   - Operations on Replication Tables
   Operations on Replicate Tables and Master Tables are given in this section. These operations are Defining Master Table, Defining Replicate Table, Undefining Replication Tables and Dropping Replication Tables.
   - Operations on Replication Relation
   Operations that creates or removes Replication Relations are described in this section. Operations on Replication Master Entry and Replication Replicate Entry that are related to Replication Relations are also explained..
   - Overriding Regular Empress Replication Controls
   Using the Replication SQL commands and Replication Utilities with Force option is explained where applicable.
   - Viewing Replication tables and synchronization status
   Getting required information about the Replication Tables and Replication Synchronization status is explained in this section.
   - Subset Replication
   Subset Replication is contrasted to Full set Replication.
   - System Attributes and System Tables related to Replication
   The additional attributes of Replication Table Records are explained, along with the reasons that Empress is using them. Also system tables that are specifically used for Replication purpose are described briefly.

5. Synchronization in Empress Replication
     The concepts and settings of Replication Master Server and Replication Synchronization Client which are the components of Client-Server model of Replication Synchronization are explained. Synchronization in Empress Replication is explained through these main sections:
   - Replication Master Server and Replication Synchronization Client
   Describes the Replication Master Server as an Empress Server. A general overview of Replication Synchronization Client as a client to Replication Master Server is described. Connection between a RMT-Side and a RRT-Side which is directly related to the Replication Master Server and its clients is explained.
   - Synchronization Utility
   Usage of Replication Synchronization Utility as a client for Replication Master Server is explained.
   - Synchronization
   The roles of Replication Master Server and Replication Synchronization Client for performing Synchronization is explained. How the Synchronization Client chooses an RMT among its Replication Master Entries is explained in detail. Requirements for a successful Synchronization is listed.

6. Empress Servers
     Empress Servers are Empress Replication Master Server and Empress Connectivity (ODBC) Server. The Empress Server Administration Utility `empsvadm` that administrates these servers is explained. The utility to analyze the logfile generated from the history of the operations performed by Empress Servers, `empsvlogstat` is also described. Empress Servers are explained through these main sections:
   - Empress Server Administration Utility
   Usage of Empress Server Administration Utility (`empsvadm`) to start and control the execution of Empress Servers is explained.
   - Configuring Empress Server and its Clients
   General configuration requirements of Empress Server are explained in this section.
   - Empress Server Log Analyzer Utility
   Empress Server Log Analyzer Utility (empsvlogstat) is used to analyze and display data from the Server Log File.
   - Password File Utility
   Password File Utility (emppassword) manages the user-created password files, which are used by Empress Servers.

7. Manual Pages
     This chapter contains manual pages for the utilities that are used for Empress Replication purpose.

1. Glossary
     This appendix gives description for Replication Specific terms that are used in this manual.

2. Scenario Scripts
     This appendix gives scripts of scenarios which are described in Empress Replication Scenarios.

3. References
     This appendix is a Reference Guide for SQL commands, environment variables, system tables and utilities related to Empress Replication. This chapter contains the following sections:
   - Introduction
   - Empress Replication SQL Commands
   A list of Replication SQL commands.
   - Empress Server Environment Variables
   Empress Server Variables are explained.
   - System Tables Related to Replication
   Information about Replication Tables, Replication Relations and Synchronization Status are stored in three system tables: `sys_rep_tables`, `sys_rep_masters` and `sys_rep_replicates`. The attributes of these system tables along with the data type and meaning of each attribute is given in this section.
   - Replication Utilities
   The utilities that are used for Replication purposes are explained: Empress Server Administration Utility `empsvadm`, Replication Synchronization Utility `emprepsync`, Empress Server Log Analyzer `empsvlogstat`. Also contents of Empress Server Log file and format of Server Start Configuration File for ODBC Server and Replication Master Server are given.
   - Restrictions on DDL and DML commands for Replication
   A list of the restrictions on Data Definition Language and Data Manipulation Language commands when used with replication tables are described in this section.
   - Examples of Viewing Replication Tables and Synchronization Status
   Examples of viewing details of a Master Table and a Replicate Table

4. Quick Start Tutorial
     This appendix gives out an example, which shows how to quickly setup and run a Replication Master Server. The example in this appendix uses a simple configuration, and performs a basic Replication Synchronization. This is not a complete guide for using Empress Replication.