This section is for the ABL (Advanced Business Language) programmer
who is not familiar with SQL. It describes how some SQL terms and concepts
differ from ABL.
Definition
SQL is the language used to communicate with and extract information
from a SQL-compliant database. Using SQL you can read, write, and remove
information from a database using English-like statements.
Rows and columns
A SQL table is a group of related data composed of rows and columns. The term row is
equivalent to the ABL term record. The term column is equivalent to the
ABL term field.
SQL column widths
An OpenEdge database can contain columns of variable length. However, SQL CREATE TABLE
statements specify the maximum width of each column in a table. Although ABL
programs have the ability to insert data whose length exceeds the maximum width, SQL
applications are not able to read a row if a column contains data greater than the
maximum width.
Note: OpenEdge contains a command-line tool called DBTOOLS that
allows you to fix column widths. See OpenEdge Data Management: Database
Administration in the
Product
Documentation section of the Progress Software Developer's Network
Web site.
Schema
In OpenEdge databases, a schema is defined as the area in which all system and user
information is stored. An OpenEdge database viewed from SQL contains a schema area,
referred to as the PUB (Public) schema. It also contains a schema called
SYSPROGRESS, which stores system catalog tables. In SQL, a schema is a collection of
related database objects, such as tables or views. A SQL database can contain
several schemas.
Note: See OpenEdge Data Management: SQL Development in the
Product
Documentation section of the Progress Software Developer's Network
Web site for information about the compatibility of ABL and SQL.