Browse Prior Art Database

Ignore Code Page Option for Relational Database Import Utility

IP.com Disclosure Number: IPCOM000036154D
Original Publication Date: 1989-Sep-01
Included in the Prior Art Database: 2005-Jan-28
Document File: 3 page(s) / 46K

Publishing Venue

IBM

Related People

Alexander, V: AUTHOR [+4]

Abstract

Disclosed is a semantic definition of a relational database import utility option which preserves data type integrity while allowing import of character data despite code page inequalities.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 51% of the total text.

Page 1 of 3

Ignore Code Page Option for Relational Database Import Utility

Disclosed is a semantic definition of a relational database import utility option which preserves data type integrity while allowing import of character data despite code page inequalities.

Character data (e.g., alphanumerics, symbols, etc.) is a fundamental data type of information stored in a relational database. Character data is represented by strings of bytes. The correlation of a specific byte to a specific character is accomplished via a mapping of byte values to character glyphs; such a mapping is called a "code page". A particular character may have numerous byte representations across the set of code pages which contain this character.

To send and receive (i.e., interchange) character data, both the code page of the sending environment (database, operating system, machine, etc.) and the code page of the receiving environment must be considered. If the code pages of the sender and receiver are not identical, a code page-to-code page transform must be part of the interchange operation to ensure that character data is preserved. Such transforms are common to many data interchange applications.

However, it is not always possible for a sender to know in advance the code page underlying the character data of a target recipient; likewise, an environment may receive character data from an unknown source. In such situations, the exchange of character data is subject to the risks of data loss or incorrect transformation. Yet, these risks may be subordinate to the need to pass data from one environment to another. Additionally, there can arise the need for environments to exchange character data despite known code page inequalities. Thus, to provide flexibility in situations such as those just described, an interchange utility must accommodate code page inequalities.

The IBM OS/2* Extended Edition Database Manager provides an Import/Export Utility for relational database interchange. This utility supports several interchange datastreams, including delimited and non- delimited ASCII, as well as the Integration Exchange Format (IXF). The IXF datastream has advantages in that it is specifically architected for relational database interchange. Not only is the data transported in the IXF datastream, but also attributes of each column of the database table are described, such as data type, length, nullability, and in the case of character data, the code page. The code page of the database itself is also included. Thus, the IXF datastream contains both the form and content of a relational database table.

The IBM OS/2 Extended Edition Database Manager Import Utility, when importing an IXF datastream, inspects the data types and code pages of the data; the semantics of this inspection vary depending upon whether the import is to a new or existing database table. In the case of import into a new table, the Utility compares the code page of both the IXF database table and each cha...