Download Week 8 - Seattle Colleges

AHE 232 Introduction to Clinical Software
Week eight:
Note: I have set up the entire curriculum for this class with weekly lesson plans. This
will allow the Instructor to determine how to incorporate the information into lesson
plans whether it is a daily class, a twice weekly class, a three times a week’s class, or
even a one class per week calendar
Queries - A request for information from a database. There are three general
methods for posing queries:
1. Choosing parameters from a menu: In this method, the database
system presents a list of parameters from which you can choose. This is
perhaps the easiest way to pose a query because the menus guide you,
but it is also the least flexible.
2. Query by example (QBE): In this method, the system presents a blank
record and lets you specify the fields and values that define the query.
3. Query language: Many database systems require you to make requests
for information in the form of a stylized query that must be written in a
special query language. This is the most complex method because it
forces you to learn a specialized language, but it is also the most powerful.
Databases
1) Sequel
a. SQL is designed for a specific purpose: to query data contained
in a relational database. (SQL is a set-based, Declarative
programming language, not an imperative language such as C
or BASIC.- this is a good time to discuss query languages)
b. Hand out article
2) Oracle
a. Have students log onto internet and do some research on Oracle
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3) Massachusetts General Hospital Utility Multi-Programming System
(MUMPS)
a. MUMPS (Massachusetts General Hospital Utility MultiProgramming System), or alternatively M, is a programming
language created in the late 1960s, originally for use in the
healthcare industry. It was designed to make writing databasedriven applications easy while simultaneously making efficient use
of computing resources. Although it never gained widespread
popularity, it was adopted as the language-of-choice for many
healthcare and financial information systems/databases (especially
ones developed in the 1970s and early 1980s) and continues to be
used by many of the same clients today. Because it predates C and
most other popular languages in current usage, it has very different
syntax and terminology. It offers a number of features unavailable
in other languages, including some rarely used programming and
database concepts.
Security Profiles
1. Putting security procedures in place to make certain that only
authorized users have access to the network, and ensuring that all security
procedures are followed
2. Discuss various types of security administration
3. Discuss what “security roles” are and how they are defined
4. Discuss how security profiles are set up – i.e., service or change
management requests
5. Who has access to Security Profiles?
LAB
•
Depending on what software is available to you, open up the area where
security profiles are stored/created. Have students set up several types of
access. Open up the Query section of the software – have students run
several pre-created queries.
Project
• Research a well known and used Database, describe what query
language it uses, give history. Attach research material to your paper.
Extra credit if you create a query (this will depend on what software you
have and if your student is able to do this.)
SQL Databases- powering today’s
Application
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SQL database is a type of database technology that is the most widely used in today's
computing environment. Here the data is stored in a very structured format that provides
high levels of functionality. SQL databases are generally more robust, secure and have
better performance than other older database technologies. It provides for 'SQL' access to
the data. So it is important to understand the term SQL before we proceed further.
What is SQL?
SQL pronounced either as "sequel" or "seekel" is an acronym for Structured Query
Language, a language developed by IBM Corporation for processing data contained in
mainframe computer databases. The relational model from which SQL draws much of its
conceptual core was formally defined in 1970 by Dr. E. F. Codd, a researcher for IBM in
his paper titled "A Relational Model of Data for Large Shared Data Banks". System/R
project began in 1974 and developed SEQUEL or Structured English Query Language.
System/R was implemented on an IBM prototype called SEQUEL-XRM during 1974-75.
Later it included multi-table and multi-user features revised as SEQUEL/2 and renamed
as "SQL".
SQL is used to create, maintain & query relational databases and uses regular English
words for many of its commands, which makes it easy to use. It is often embedded within
other programming languages. A fundamental difference between SQL and standard
programming languages is that SQL is declarative. You specify what kind of data you
want from the database; the RDBMS is responsible for figuring out how to retrieve it.
SQL Standards
SQL, the most popular relational database language was first standardized in 1986 by the
American National Standards Institute (ANSI). Since then, it has been formally adopted
as an International Standard by the International Organization for Standardization (ISO)
and the International Electrotechnical Commission (IEC). Although SQL is both an ANSI
and an ISO standard, many database products support SQL with proprietary extensions to
the standard language.
Database Language SQL is under continual development by the above mentioned
standardization bodies. At present there are two committees that are working to ensure
SQL standards - an International committee (ISO/IEC JTC 1/SC 32/WG 3) & an
American committee (ANSI TC NCITS H2).
After 1986, a revised standard known commonly as SQL-89 or SQL1 was published in
1989. Due to partially conflicting interests from commercial vendors, much of the SQL89 standard was intentionally left incomplete, and many features were labeled
implementer-defined. In order to strengthen the standard, the ANSI committee revised its
previous work with the SQL-92 standard ratified in 1992 also called SQL2. This standard
addressed several weaknesses in SQL-89 and set forth conceptual SQL features, which at
the time exceeded the capabilities of any existing RDBMS implementation. In fact, SQL92 standard was approximately six times the length of its predecessor. In 1999, the
ANSI/ISO released the SQL-99 standard also called SQL3. This standard addresses some
of the more advanced and previously ignored areas of modern SQL systems such as
object-relational database concepts, call level interfaces, and integrity management.
Basically, SQL-99 replaces the SQL-92 levels of compliance (Entry, Intermediate, and
Full) with its own degrees of conformance - Core SQL-99 and Non-core (Enhanced)
SQL-99. Recently, in 2003, ANSI/ISO released the SQL-2003 standard also called SQL200n. The big SQL-2003 features are: more collection data types, cleaner
object/relational specification, and references to new parts such as XML. The big missing
SQL-2003 feature is the SQL-99 standard BIT data type.
From the above discussion, it is clear that the three editions that matter today are:
SQL-92 the previous standard
SQL-99 the current standard
SQL-2003 the evolving standard
Technology standards are important for several reasons - number one being that
consumers are assured of what the product is supposed to do before they buy it. There are
also several benefits to having a standard - for one, third-party vendors are able to create
tools and utilities that apply to an entire market rather than to a specific platform.
Similarly, individuals can become certified in a standard, increasing the size of your
available resource pool. Product certification can help ensure quality functionality, as
opposed to the pseudo-implementation of standards requirements by compliant, but not
certified, solutions.
Daffodil DB presently conforms to most of the Entry - Level SQL92 standard, as well as
many of the Intermediate- and Full-level features
List of Key SQL-99 Features
Working of 'SQL' in SQL database
The basic structure of the relational model of an SQL database is a table, consisting of
rows and columns. Data definition includes declaring the name of each table to be
included in a database, the names and data types of all columns of each table, constraints
on the values in and among columns, and the granting of table manipulation privileges to
prospective users. Tables can be accessed by inserting new rows, deleting or updating
existing rows, or selecting rows that satisfy a given search condition for output. Tables
can be manipulated to produce new tables by Cartesian products, unions, intersections,
joins on matching columns, or projections on given columns.
SQL data manipulation operations may be invoked through a cursor or through a general
query specification. The language includes all arithmetic operations, predicates for
comparison and string matching, universal and existential quantifiers, summary
operations for max/min or count/sum, and GROUP BY and HAVING clause to partition
tables by groups. Transaction management is achieved through COMMIT and
ROLLBACK statements. <TI LEVELS>
The standard provides language facilities for defining application specific views of the
data. Each view is the specification of database operations that would produce a desired
table. The viewed table is then materialized at application execution time.
<UPDATABLE VIEW>
The SQL standard provides a Module Language for interface to other languages. Each
SQL statement may be packaged as a procedure that can be called and have parameters
passed to it from an external language. A cursor mechanism provides row-at-a-time
access from languages that can only handle one row of a table at one time.
Access control is provided by GRANT and REVOKE statements. Each prospective user
must be explicitly granted the privilege to access a specific table or view using a specific
statement. <ROLE>
The SQL Integrity Enhancement facility offers additional tools for referential integrity,
CHECK constraint clauses, and DEFAULT clauses. Referential integrity allows
specification of primary and foreign keys with the requirement that no foreign key row
may be inserted or updated unless a matching primary key row exists. Check clauses
allow specification of inter-column constraints to be maintained by the database system.
Default clauses provide optional default values for missing data.
The Embedded SQL specification provides SQL interface to programming languages,
specifically Ada , C, COBOL, FORTRAN, MUMPS, Pascal, and PL/I. Applications may
thereby integrate program control structures with SQL data manipulation capabilities.
The Embedded SQL syntax is just shorthand for an explicit SQL Module accessed from a
standard conforming programming language.
SQL-92 significantly increases the size of the original 1986 standard to include a schema
manipulation language for modifying or altering schemas, schema information tables to
make schema definitions accessible to users, new facilities for dynamic creation of SQL
statements, and new data types and domains. Other new SQL-92 features include outer
join, cascade update and delete referential actions, set algebra on tables, transaction
consistency levels, scrolled cursors ,deferred constraint checking, and greatly expanded
exception reporting. SQL-92 also removes a number of restrictions in order to make the
language more flexible and orthogonal. Daffodil DB does support all the above
mentioned features. As regards SQL-92, Daffodil DB can be placed somewhere midway
between Intermediate and Fully compliant levels.
The major features that are introduced in SQL-99 are regular expression matching,
recursive queries, triggers, non-scalar types and some object-oriented features. Daffodil
DB supports all the above listed features with the exception of object-oriented features.
Major features in SQL-2003 are: XML-related features, window functions , standardized
sequences and columns with auto-generated values (including identity-columns). All the
above features are included in the Road map of Daffodil DB.
Advantages of SQL databases
High speed
SQL queries are designed to retrieve large amounts of records from a database quickly
and efficiently. With the help of simple SQL queries, you can retrieve even highly
complicated combination of data from the database. SQL databases are also much
more adept at handling very large volumes of data and processing it quickly when
compared to non-SQL databases
Security
With the SQL database storage, you get the security of all the data being in one place,
which you can manage easier
Well-defined standards exist
SQL databases use the long-established SQL (Structured Query Language) standard,
which has been adopted by ANSI in 1986 and since then continually evolving by the
efforts of ANSI & ISO, the latest being SQL-2003. On the contrary, non-SQL
databases do not have clear standards to adhere
Compatibility
This is the direct fallout of the previous point regarding standards. Since well-defined
and established standards exist, and if the databases adhere to those, then portability
from one SQL database to another is a trivial matter. Further, an SQL database
conforming to set standards can be easily accessed by third party softwares and
application tools. This will facilitate the development of quality applications and
solutions around SQL databases
No coding required
By using standard SQL it should be easier to move applications between different
database systems without the need to rewrite a substantial amount of code
Emergence of ORDBMS
Previously SQL databases were synonymous with relational databases. With the
emergence of ORDBMS (Object-Relational Database Management Systems), object
storage capabilities are extended to relational systems. On the other hand, power of
SQL can now be made use in OODBMS as well
Disadvantages of SQL databases
Premature Codification
Also known as "fast setting concrete", this refers to the fact that in SQL, you must
define your tables and fields and the relationships between them, pretty much before
you can do anything else. This is fine with the initial version of your application, but
for another major version, you typically want to change your tables and fields all
around. At the same time, you also want to ensure that the new version is compatible
with the old version to make your users happy. In SQL, you have to write a lot of extra
code to achieve this. Dealing with intermediate versions is almost worse: adding small
things for 'your version 1.1' often cause changes to cascade through your code. So it
can be concluded that SQL databases may be great for mature applications. But for
rapidly-developing new applications, it can be a real blocker to progress
No Automatic Table-to-Object Mapping
If you code in an object-oriented style, you will find yourself developing a layer
whose only function is to map SQL tables to the objects that your program really uses,
and then back again. This is a real waste of time and effort, and one can easily leave
with the impression that this process can almost be automated. The work-around
would be 'SQL object persistence-on-demand', a tool that will automatically take an
instance of your object and, on command, store into or retrieve from an SQL database
Difficulty in interfacing
Since an SQL database supports many advanced features, interfacing to an SQL
database is more difficult than adding a few lines of code
More features implemented in a Proprietary way
Although SQL databases conform to the SQL standards adopted by ANSI & ISO,
some databases go for proprietary extensions to standard SQL so as to ensure vendor
lock-in. Daffodil DB is an SQL database that almost conforms to SQL-99
specifications and does not have any proprietary extensions
Major SQL databases
Conclusion:
Hopefully this article has served to demystify SQL databases and how to start using
them. We now know that a SQL database is just a handy and structured place to put all
our data. This article has given us an introduction to the history of SQL databases,
models of SQL and what role SQL play in the functioning of SQL databases.
We are now aware of what a SQL database is for, what its features, merits and demerits
are and the available SQL database options in the market. This article also focuses on
SQL99 and some of its key features.
Security and Compatibility are two most significant features of SQL databases. Storing
data in a SQL database is more secure than ever before. SQL databases are compatible
with almost all technologies which is probably the strongest reason of its wide
acceptance. In SQL databases, the operations can be performed within the time
constraints, as high speed query execution is another vital advantage of SQL databases.
In this article, we have also pointed out the features of ORDBMS and the flavours it is
available in.
The difference between advantages and disadvantages of SQL databases is narrowing day
by day as developers are putting severe efforts in making SQL databases as user-friendly
as possible. So we can expect some considerable improvements in the features of existing
SQL databases in near future.