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The Antelope Relational Database System
Datascope: A tutorial
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Boulder Real Time Technologies, Inc. reserves the right to make changes at any
time and without notice to improve the reliability and function of the software
product described herein.
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transmitted, in any form or by any means, electronic, mechanical, photocopying,
recording, or otherwise, without prior written permission of Boulder Real Time
Technologies, Inc.
Copyright © 2002 Boulder Real Time Technologies, Inc. All rights reserved.
Printed in the United States of America.
Boulder Real Time Technologies, Inc.
2045 Broadway, Suite 400
Boulder, CO 80302
Datascope: A Tutorial iii
CHAPTER 1 Overview 1
Datascope: What is it? 1
Datascope: Features 2
Datascope: What is it good for? 3
CHAPTER 2
Test Drive 5
What is a relational database? 6
dbe: a window on a database 6
Viewing a table 7
Viewing schema information 7
Performing a join 9
What about the join conditions? 10
Arranging fields in a window 11
Viewing data in a record view 12
Other database operations 13
Creating a subset view 14
Using dbunjoin to create a subset database 15
Editing a database 16
Simple graphing 17
Summary 19
CHAPTER 3
Schema and Data Representation 21
Database Descriptor Files 21
Representation of Fields 22
Schema Description File 23
Schema Statement 23
Attribute Statement 24
Relation Statement 25
Datascope Views 26
Reserved Names for Fields and Tables 27
A word of caution regarding id fields 29
CHAPTER 4
Basic Datascope Operations 31
Reading and Writing Fields and Records 31
Deleting Records 31
iv Datascope: A Tutorial
Subsets 32
Sorts 32
Grouping 32
Joining Tables 32
Inferring Join Keys 34
Inheritance of keys 34
Specifying Join Keys 35
Speed and efficiency 35
Summary 36
CHAPTER 5
Expression Calculator 37
Basic Operators and Database Fields 38
Data Types 39
String Operations 39
Logical Operators 41
Assignments 43
Standard Math Functions 43
Time Conversion 44
Spherical Geometry 45
Seismic Travel Times 46
Seismic and Geographic Region functions 47
Conglomerate functions 48
External functions 48
CHAPTER 6
Programming with Datascope 49
Sample Problem 50
At the command line 52
Database pointers 53
A few programming utilities 54
Error Handling 55
Time conversion 55
Associative Arrays 56
Lists 56
Parameter files 56
Overview of tcl, perl, c, and fortran solutions 56
Tcl/Tk interface 57
The perl interface 59
The c interface 60
Datascope: A Tutorial v
The FORTRAN interface 61
Summary 63
CHAPTER 7 Datascope Utilities 65
dbverify 65
dbcheck 65
dbdiff 66
dbdoc 66
dbset 66
dbfixids 66
dbcrunch 66
dbnextid 66
dbcp 67
dbremark 67
dbaddv 67
dbcalc 67
dbconvert 67
dbdesign 67
dbinfer 68
dbdestroy 68
vi Datascope: A Tutorial
Datascope: A Tutorial 1
CHAPTER 1 Overview
Antelope is a collection of software which implements the acquisition, distribution
and archive of environmental monitoring data and processing. It provides both
automated real time data processing, and offline batch mode and interactive data
processing. Major parts of both the real time tools and the offline tools are built on
top of the Datascope relational database system. This tutorial explains some basic
concepts behind relational database systems and how these concepts appear in
Datascope.
Datascope: What is it?
Datascope is a relational database system in which tables are represented by fixed-
format files. These files are plain ASCII files; the fields are separated by spaces and
each line is a record. The format of the files making up a database is specified in a
separate schema file. The system includes simple ways of doing the standard opera-
tions on relational database tables: subsets, joins, and sorts. The keys in tables may
be simple or compound. Views are easily generated. Indexes are generated automat-
ically to perform joins. General expressions may be evaluated, and can be used as
the basis of sorts, joins, and subsets.
The system provides a variety of ways to use the data. There are c, FORTRAN,
tcl/tk and perl interfaces to the database routines. There are command line utilities
which provide most of the facilities available through the programming libraries.
Overview
2 Datascope: A Tutorial
There are a few GUI tools for editing and exploring a database. And, since the data
is typically plain ASCII, it’s also possible to just use standard UNIX tools like sed,
awk, and vi.
Datascope: Features
• Datascope is small, conceptually simple, and fast.
• Datascope has interfaces to several languages (c, FORTRAN, tcl/tk, perl and
MATLAB), a command line interface, and GUI interfaces. These provide a
wide range of access methods into databases.
• Datascope does not provide access through a specialized query language, such
as SQL.
• Datascope provides most of the features of other commercial database systems,
including:
•data independence
•schema independence
•view generation through joins, subsets, sorts, and groups
•automatic table locking to prevent database corruption when multiple users
are adding records to a table
• The organization of tables and fields within a Datascope database is specified
with a plain text schema file. This schema file, in addition to specifying the
fields which make up tables, and the format of individual records in every table,
provides a great deal of additional information, including:
•short and long descriptions of every attribute and relation
•null values for each attribute
• a legal range for each attribute
•units for an attribute
•primary and alternate keys for relations.
• foreign keys in a relation
This additional information is useful for documenting a database, and makes it easier
for a newcomer to learn a new database.
Datascope: A Tutorial 3
• The detailed schema often makes it possible to form the natural joins between
tables without explicitly specifying the join conditions.
• Datascope schema files and database tables are stored in normal ASCII files on
the UNIX file system. These files can be viewed and edited using normal text
editors (although it is inadvisable to hand edit database tables). File access per-
missions are controlled through the normal UNIX file permissions.
• The keys in Datascope tables may include ranges, like a beginning and an end-
ing time. This is useful, and sometimes essential, for time dependent parame-
ters, like instrument settings. Indexes may be formed on these ranges, and these
indexes can considerably speed join operations. (When two tables are joined by
time range keys, the join condition is that the time ranges overlap.)
• Datascope has an embedded expression calculator which can be used to form
joins, sorts and subsets. This calculator contains many functions which are
peculiar to environmental science applications, such as spherical geometry,
exhaustive time conversion functions and seismic travel time functions.
Datascope: What is it good for?
Relational database systems are a proven method for representing certain types of
information, much more powerful than the traditional grab-bag approach of data
files, log files, handwritten notes, and ad hoc data formats. Datascope is a general-
purpose relational database management system which is ideal for managing the
large and complex data volumes that are produced by a modern environmental
monitoring network. It is relatively easy and intuitive when compared to other com-
mercial database products. It provides a way of moving from the traditional pleth-
ora of formats to a better approach which organizes the data, documents it, and
provides powerful tools for manipulating it.
Datascope should be useful to anyone who needs to organize data and is interested
in applying relational database technology, but can’t afford the time, learning,
development, and people resources which most other commercial database systems
require.
Overview
4 Datascope: A Tutorial
[...]... instruments (location, gains, orientation) This is the “raw data” part of the database In addition, the database contains information which is derived from the raw data, typically information about earthquakes: location, size, and first arrivals of seismic energy from various earthquakes at the various stations Datascope: A Tutorial 5 Test Drive What is a relational database? A database can be any collection...CHAPTER 2 Test Drive Learning a database system such as Datascope takes some time and involves at least the following steps: • learning about relational databases in general • learning the tools and operations a particular DBMS provides • learning a particular database schema • learning a particular database This chapter gives a whirlwind tour of a small example database, using the general purpose Datascope... is a variation of a schema developed at the Center for Seismic Studies A standard reference text for databases is “An Introduction to Database Systems”, by C.J Date Start with it if you would like to learn more about relational databases in particular dbe: a window on a database dbe is a general purpose tool for exploring, examining, and editing a relational database It provides in a single interactive,... and the table name, i.e database. table Typically, all the tables which make up a database are kept in a single directory However, there is also provision to keep certain tables in a central location, but have multiple versions of other tables in other locations Database Descriptor Files Datascope understands a descriptor file which specifies a few important parameters: • the database schema name • a path... Schema and Data Representation The database path specifies a path along which to look for the files while hold the database tables For any particular table, the first file matching the table name found along the path must contain the table The last two parameters are optional; they relate to table locking performed during the addition (not deletion nor modification) of records The default is no locking The. .. specialized use, and the primary value of Datascope comes in its use in programs 20 Datascope: A Tutorial CHAPTER 3 Schema and Data Representation Datascope keeps tables as plain ASCII files Each line is a separate record, and the fields occupy fixed positions within each line (There is no variably sized text field.) The name of a file which represents a table is composed of two parts the database name and... information, hopefully organized in some fashion that makes it easy to find a particular piece of information Relational databases organize the data into multiple tables Each table is made up of records, and each record has a fixed set of fields (sometime referred to as “attributes”) The structure of a database, i.e the tables and the fields which make up a record, is called the schema The schema for our... general purpose Datascope tool dbe This will get your feet wet, show you quickly how to do a variety of useful things, and get you started learning about relational databases in general, and Datascope in particular Datascope was originally developed for seismic applications and the demo database has seismic data It contains data recorded at seismic stations around the world and parameter data describing... along which various tables of the database may be found • the table locking mechanism • central id server The schema name is used to look up a schema file This file is typically kept in $ (ANTELOPE) /data/schemas, but may instead be kept in the directory with the database descriptor this provides a means of testing alternative or modified schemas prior to installing them centrally Datascope: A Tutorial. .. subsets of the table by typing an expression in the Subset entry area, and you can change the scales to log scales The plot can be saved as postscript, yielding a higher resolution than the screendump above Summary This short tour of the demo database has introduced the dbe interface, and shown how to do simple joins, subsets, and sorts, as well as how to extract a small database from a large database By . of the Datascope relational database system. This tutorial explains some basic
concepts behind relational database systems and how these concepts appear. most other commercial database systems
require.
Overview
4 Datascope: A Tutorial
Datascope: A Tutorial 5
CHAPTER 2 Test Drive
Learning a database system
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