Databases have become a common part of our lives but do we really know what makes them function to serve us the information we need? Sumathi & Esakkirajan (2007) explain that an electronic database is a collection of data that have been logically arranged and can be accessed in various ways through the use of a database management system or DBMS. It should be noted that data are a representation of instructions, concepts, ideas and facts in a formalized fashion that permits the transmission, processing, or analysis of information with the assistance of the computer (Sumathi & Esakkirajan, 2007).
How are electronic databases related to electronic libraries? We know that a library is a collection of books and other printed material, although this has broadened to include other ways of storing information, such as films and CD-ROMs. Akeroyd (2002) observes that the continuous progress in computer technology has led to the development of electronic, digital or virtual libraries.
He notes that the developments related to electronic libraries started with the computerization of library catalogs in the early 1970s that was followed by the creation of integrated library systems (ILS) that utilized one software architecture to handle the key processes required by libraries, such as acquisitions, circulation, cataloging, inter-library loan systems, and financial control. He believes that the most important development for the creation of electronic libraries was the Online Public Access Catalog or OPAC.
He stresses, however, that there are several technical barriers for the realization of the true electronic library. The foundation of the electronic library is, of course, the DBMS because it is a program that enables the user to gain access to the stored data in a number of ways. Sumathi & Esakkirajan (2007) explain that the DBMS permits the user to enter data, modify the data, and show the data on the monitor. In business applications, these data may include information about employees, management, customers, and suppliers.
In an electronic library, the data will include the pages of a certain book or journal, or sound and video recordings. According to Sumathi & Esakkirajan (2007), the primary purposes of the DBMS include data integrity, data availability, data independence, and data security. Data independence means that the system does not reveal certain details about the procedures followed when the data are manipulated, maintained, and stored. Data integrity ensures that the data that are kept in the database have not been corrupted or erroneous.
Data security means confidential information cannot be accessed by those who are not supposed to get them. Data availability means that data could be accessed at affordable prices by a broad range of people, subject to confidentiality restrictions. Availability is an important aspect in electronic libraries and what is often proposed is one point of access to the whole collection, which has been sufficiently scoped to comply with the requirements of the users (Akeroyd, 2002).
However, Pinfield (2001) notes that pricing in the electronic library market is still quite young with prices for e-journals being determined by complicated equations that are often based on pricing for print subscriptions. It has also been observed that electronic libraries are more costly, which is ironic because the eLib project in the UK was motivated by the desire to reduce space and expenses (Pinfield, 2001). Before continuing with the subject of electronic libraries, let us first trace the history of databases.
The origin of the DBMS is the file-based system that was called Generalized Update Access Method or GUAM, which was developed by Rockwell International that was then known as North American Aviation (Sumathi & Esakkirajan, 2007). GUAM was originally designed for the moon-landing process of the Apollo missions but IBM later collaborated with North American Aviation to develop the hierarchical Information Management System or IMS. At about the same time, General Electric developed the network data-structured Integrated Data Store or IDS (Sumathi & Esakkirajan, 2007).
The IDS was capable of handling data relationships that are more complex than those that could be handled by hierarchical databases like the IMS. Because the IMS and IDS systems had certain deficiencies, such as the need for complicated procedures to access data and reduced data independence, IBM developed the Structured Query Language (SQL) in the late 1970s. With SQL as basis, Oracle and IBM released their own brands of relational DBMSs in the 1980s. The relational databases were followed by object-relational and object-oriented databases, and the current Web-enabled DBMSs in the 1990s (Sumathi & Esakkirajan, 2007).
Despite the advances in database technology, technical problems still challenged the realization of digital libraries with regards to the integration of the various parts of the library to present a consistent whole (Pinfield, 2001). Akeroyd (2002) points out that the emergence of web-based databases has added to the technical challenges faced by electronic libraries, such as ILS. To be able to cope with both printed materials and electronic resources, information professionals have come with the idea of hybrid libraries (Akeroyd, 2002).
Among these hybrid libraries is the eLib project in the UK (Pinfield, 2001). Let us focus our attention on the original file-based system to comprehend the reasons for the need to develop DBMS and its more complex forms. The file-based system is similar to the file cabinets used in keeping paper records in that there are several applications that provide specific services for the users (Sumathi & Esakkirajan, 2007). For example, there may be one program for keeping and accessing information on the leaves filed by employees, while another program is focused on negotiations with suppliers.
It can be seen that because data are kept in separate files, there could be duplication, use of different file formats, separation between various data so that searching the various files would be a tedious process, and data dependence (Sumathi & Esakkirajan, 2007). Because each file may require a different application to access it, the tendency would be that the files would have different formats, thereby presenting a hindrance to combining the files into one. Another problem is the possible duplication of data so that valuable storage space is wasted.
Imagine having the same information kept in three or more files! Moreover, it is often the case that the application or program is dependent on structure of the storage of the data, thereby causing a need to alter the program when there is a change in data structure (Sumathi & Esakkirajan, 2007). The DBMS is designed to remedy the above-mentioned problems with file-based systems, and thus, it provides data independence, centralized data management, and system integration (Sumathi & Esakkirajan, 2007).
With data independence, the applications no longer need to worry about the structure of the database because all they need to do is interact with the DBMS’s interface. With centralized data management, a single system is in charge of all data and the database is no longer made up of separate files, thus making it easier to look for information (Sumathi & Esakkirajan, 2007). Another important aspect of the electronic database is the data model, which is designed to specify the consistency constraints, data relationships, and the data themselves (Sumathi & Esakkirajan, 2007).
The data models utilized during the 1960s and 1970s were the network and hierarchical models that were concerned with the links between the various data structures. The problem with these early versions was that they were interrelated to the physical modeling of data and did not provide much data independence. To provide a remedy for these deficiencies, the relational data model was devised by IBM that later led to the establishment of SQL (Sumathi & Esakkirajan, 2007).
The database administrator is responsible for centralized control of the applications and the data involved in the DBMS. He is also involved in the planning of the setup of the system. He is also responsible for making sure that all documentation regarding the implementation and the standards are current. The administrator is also tasked with evaluating every design step to determine whether it is possible from the point of view of the electronic database. He will also design the standards that will be helpful in developing the applications that will utilize the database.
He will also make sure that the integrity of the data is protected in case of unexpected events and that there would be no unauthorized access. In summary, the database administrator is in charge of authorizing the users who will be permitted to access data, acquiring the programs and equipment as the need arises, monitoring and managing the use of the database, and making sure that a backup is regularly conducted (Sumathi & Esakkirajan, 2007). The database designer is another important personnel involved with electronic databases. He can either be a logical designer or a physical designer.
The logical designer must be well-versed with regards the organizations data and its corresponding business rule while the physical database designer takes the output from the logical designer and develops a way to implement it in the physical database. The logical designer chooses the storage structure, maps the logical data model into a set of integrity constraints and tables, and specifies the security measures to be adopted (Sumathi & Esakkirajan, 2007). To enable a systematic way to access data within the electronic database, a data dictionary that contains metadata is employed (Sumathi & Esakkirajan, 2007).
The metadata are the data types, the various fields, the primary keys, the joins between tables, indexes, and referential integrity, among others. It is the data dictionary that is consulted by applications utilizing the database and by the programmers (Sumathi & Esakkirajan, 2007). The simplest way to implement the DBMS is through a two-tier architecture, where the first tier (also known as the “client”) is mainly responsible for displaying the data to the user and the second tier (also known as the “server”) offers data services to the first tier (Sumathi & Esakkirajan, 2007).
The “client” or first tier provides the user interface for interacting with the user and a range of application services, while the second tier or “server” offers data access without having to be concerned about data location. The two-tier architecture for electronic databases is the simplest to implement but it has several deficiencies such as the possibility that the database server will be swamped by managing messages and the difficulty in maintaining the software (Sumathi & Esakkirajan, 2007). To offer a remedy for these defects, the multi-tier architecture can be utilized.
Basically, at least one tier is inserted between the client and the server to permit a single application to use various kinds services that may be found on different platforms (Sumathi & Esakkirajan, 2007). It can be seen from the above discussion that the DBMS offers a way to store and modify information in an efficient way and this capability is applicable to digital libraries. The difference between electronic databases and electronic libraries is that the latter are specifically designed for books, journals, and other forms of information that have been usually thought to reside in traditional brick-and-mortar libraries.
To address the special requirements of libraries, the OPAC is supposed to play the central role in digital libraries as a way to access the various contents of the database. However, with regards to hybrid libraries, where the digital library is linked with web-based resources and the traditional library, the role of OPAC is still uncertain (Pinfield, 2001). He notes that several libraries have already established websites that permit the user to directly access the information resources through them. These sites usually contain links that lead the user directly to certain e-journals or e-books.
He adds that the website has now become a search tool that no longer requires OPAC. Akeroyd (2002) also observes that one of the biggest challenges to the popularity of the Integrated Library System or ILS is the Web. He explains that libraries have had to include the various emerging services and sometimes attempted to utilize them based on the structure of the traditional library. Pinfield (2001) also notes that an often neglected problem in digital libraries is the identity of the user to be able to ensure that the user is authorized to access a particular licensed resource.
Akeroyd (2002) points out that the management of change is a key issue in the move to electronic libraries. These include economic issues because of the need for libraries to have two subscriptions for both traditional and electronic media. Social issues are also involved because some users still prefer the traditional format and dislike it when they are offered the electronic format. Meanwhile, Pinfield (2001) stresses the importance of looking at the organizational issues because library personnel need to collaborate closely with those in the IT department.
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