RDBMS

RDBMS is a Database Management System that is based on the relation model. Relational here is a key word for RDBMS. You will find that data is stored in the form of Tables and the relationship among the data is also stored in the form of tables for RDBMS.

Table

Table is a key component within a database. One table or a group of tables represent one kind of data. For example, table OSLP within SAP Business One holds all Sales Employee Data. Tables are two-dimensional data storage place holders. You need to be familiar with their usage and their relationships with each other. If you are familiar with Microsoft Excel, the worksheet in Excel is a kind of two-dimensional table.

Table is also one of the most often used concepts in the book. Relationships between each table may be more important than tables themselves because without relation, nothing could be of any value. One important function within SAP Business One is allowing User Defined Table (UDT). All UDTs start with"@".

Field

A field is the lowest unit holding data within a table. A table can have many fields. It is also called a column. Field and column are interchangeable. A table is comprised of records, and all records have the same structure with specific fields. One important concept in SAP Business One is User Defined Field (UDF). All UDFs start with U_.

SQL

SQL is often referred to as Structured Query Language. It is pronounced as S-Q-L or as the word "Sequel". There are many different revisions and extensions of SQL. The current revision is SQL: 2008, and the first major revision is SQL-92. Most of SQL extensions are built on top of SQL-92.

This book has very specific scope for the terms "SQL" and "query". Please read through this section carefully first if you find that the scope of the book is not right for your needs.

T-SQL

We have to limit the scope of the term SQL in this book. First of all, since SAP Business One is built on Microsoft SQL Server database, SQL here means Transact-SQL or T-SQL in brief. It is a Microsoft's/Sybase's extension of general meaning for SQL. Because we only use T-SQL throughout the book, SQL in this book will mean T-SQL unless it is clearly mentioned otherwise.

Subsets of SQL

There are three main subsets of the SQL language:

Each set of the SQL language has a special purpose:

Query

Query is the most common operation in SQL. It could refer to all three SQL subsets. In this book, however, you will only learn the read-only part of the query. No Add, Delete, or Update SQL statement in DML will be discussed in the book since it is prohibited from SAP support policy for SAP Business One database integrity. All DCL or DDL SQL will also not be included because we neither control access to data in a database, nor define data structure for a database. You will find SELECT leading query only within the book. Read-only query SELECT has powerful functionality for finding useful information to meet your specific needs.