..QUIT

Next day when we start the dBASE III programme, we must first indicate which file we want to use, otherwise dBASE III will not know which file we are interested in. The command for this is

..USE CUSTLIST

Now let us say we want to query on the customer data for extracting different types of information. Here is a sample list to illustrate how easy it is. 
 

One has to learn only few additional features to see how sales and receipt transactions can be used to update amount due for each customer. The dBASE III package also has REPORT command for producing user specified reports. With the command verbs, dBASE III also provides conventional programming features like IF-THEN-ELSE, WHILE-DO. A complete set of dBASE III programmes can be designed to implement a medium sized application in a couple of weeks.

It is more often easy and practical to identify the new customer revenue and the existing customer growth from the accounting database. The information at the individual customer level will give a fairly good idea about the customer migration. 

Customer Migration 

The measurement of customer migration is identifying what happens to individual customers during a specific period of time. The individual customer may either totally defect at a high value point in their life cycle. For example, a company can spend Rs. 10,00,000 on a campaign to acquire new customers who may really be valuable only during 2005 or spend Rs. 5,00,000 to retain customers who are profitable now.

..APPEND

With this command we get a screen which provides a blank customer record. As the name implies, this command will append a record to our CUSTLIST file. Thus, it can be used whenever we want to add one more customer to customer list. With the customer we can add product fulfillment types. Product given to customer gives them product fulfillment or order fulfillment. We can add any criteria for that.

In the screen provided with above command, we now type the necessary details of a customer. The names of the fields are displayed on the screen to facilitate entry of data for a customer for which we wish to create a record in CUSTLIST file. After we type in all the required details about the customer and type e get another blank record in which we can enter data about next customer and so on. When we type right at the beginning of blank record we get back to dot prompt where we can issue a new dBASE III command.

..CREATE CUSTLIST

Note the keyword CREATE which is typed by the user against the dot prompt produce by dBASE III. CREATE command wants a parameter which will be used as a name for the file so created. The user can choose any name that he desires within the syntactic rules specified by the package. We shall henceforth omit such minor syntactic details of the package. We shall use the symbol to indicate enter or return key of the keyboard. In response to CERATE command, dBASE III will provide a screen where we can enter the above nine filed names alongwith their type characteristics.

For a customer file we want each record to have nine fields: one each for the items listed above. In dBASE III, it is necessary to give names to each of these nine fields so that they can be later referred to using these names. The field names which we have chosen are shown in the third column above. Apart from the name, we have to also indicate what type of data will be stored in the field and in certain cases number of characters to be reserved to hold the data for that field. We will want AMOUNTDUE and CRDLMT to hold numeric data and all other fields to hold text or character data. Now let us have a quick look at a dialogue in dBASE III for creating and using such a file.

Like other DBMS packages, dBASE III provides features for: 

1.      Creating data files on a computer.

2.      Maintaining these data files by way of providing functions for adding, deleting editing and updating a give set of data items.

3.      Generating reports based on the data files created through dBASE III

4.      Querying on those data files.

To develop an understanding of the features provided by dBASE III package, let us take a specific application and see how it could be implemented in dBASE III. Suppose we are operating a small business house which has 1000 customers. We are interested in maintaining a list of these customers and using this list for our day-to-day business operations. Obviously we will have to create a file which contains data about these 1000 customers. In this file there will be one record for each customer. Thus, we will have a file containing 1000 records.

1.      It is easy to use and is simple. Its basic features can be learned in a couple of hours.

2.      It provides a very high level language interface which is command oriented. Some people consider it a fourth generation language. In lay man’s terms, fourth generation language means it is superior to standard programming languages like BASIC, COBOL, FORTRAN and PASCAL; and it simplifies and sometimes even avoids programming in a conventional sense.

3.      Small business information systems can be easily implemented in a few days using this package. Insurance CRM or instant life insurance rates application can be implemented easily in small businesss.

4.      This package can be used as a tool to prototype large applications. Prototyping is useful for saving costs in implementing large applications. Parts of a large system may be implemented through dBASE III package to finalize specifications of what users want through the envisaged application and how these parts could possibly be implemented in their final form.

We will discuss some features of the DBMS packages in our next post.

1. Data Base Management Software
2. Spreadsheet Software
3. Word Processing Software
4. Graphic Software
5. Data Communication Software

Data Base Management

Software packages called Data Base Management System (DBMS) has been developed long before micro-computers to handle the problems of maintaining and integrating large volumes of data on large machines. The most important distinguishing feature of a DBMS package on personal computers is that it provides a very high level language interface which can be learned by a user who is not a computer programmer. In a few hours, it is possible to acquire enough skill to use the basic features of DBMS packages like dBASE III which is the best selling software currently in this class.

To support such networking special electronic devices such as modems an network inter-face cards are often fitted into micro-computers. For example, a blinds company who are selling vertical blinds and roman shades online, they are having inter-linked computers by which they are sending their marketing emails. Another example is a company who are providing term life insurance rates online, they are using lead management tools by which their online leads are transfer to their insurance software and from that insurance software they are distributing their leads.

As with large computers, micro-computers have operating systems to enable the user to easily interact with the machine. These operating systems are similar to those on large machines except that they are much simpler. This is because the majority of micro-computers are not multi-terminal machines – only one user has access to the machine at any time. In this situation the machine is the personal computer of the user. Personal computers are used for a variety of tasks. The most common applications are:

1. Word Processing
2. Financial Analysis
3. Data Base Access
4. Graphics
5. Accounting

The main memory is made from several chips. These may be ROM or RAM chips.  ROM (Read Only Memory) chips contain instructions permanently written in the memory. The contents of these chips cannot be altered. RAM (Random Access Memory) Chips provide the memory that can be read from, written into and cleared.

Most micro-computers have between 16 K bytes and IMB memory. The typical word-size of micro-computers when they were introduced in business in the late seventies was B-bits. Today, the most common word-size is 16-bits. It is virtually certain that in the next few years 32-bit micro-computers will be very common although today their numbers are somewhat limited due to cost and scarcity of software. Dot matrix and daisy-wheel printers are popular printing devices on micro-computers.