Database Management with MS Access

Learning Objectives

• Concepts of database management systems (DBMS)

• Relevance in agricultural research

• Developing simple applications in database management using MS Access

Definition Database management systems are the means to transform data into information for analysis, evaluation, and decision making. The word database nowadays implies a computer based system. But, in general databases have existed in different forms. Some familiar examples are: Paper sheets in files Scientists Literature Reference cards A book Books in a library Telephone directory Dictionary Maps Soil samples DNA samples Letter Dispatch register Video library, etc.

All of these are organized sets of information with some kind of an indexing system which facilitates access to and search for specific information ( eg. indexing systems for files, papers/letters; table of contents in a book; the alphabetical order of arrangement of words in dictionary; the alphabetical order and classification system in a telephone directory; subject or author based classification of reference cards by individual scientists; the classification of books in library; the coding systems used by scientists for storing and retrieving samples; etc.). These examples illustrate how information is organized in databases and accessed for use. A database management system is a computerized database with features similar to the above databases. It is a software programme that permits the creation of databases and work with the data in them.

Definition: Database management systems (DBMS) are computerized systems fororganizing, storing, retrieving, updating and analyzing large and related data quickly andefficiently to provide useful information for decision-making for specific purposes andsituations.

Large in the above definition refers not only to the size but also to the variety of data contained in the database.

Relevance to agricultural research Data are valuable resources in agricultural research. They are generated at considerable expense. Much of the agricultural research data is generated over several seasons through multidisciplinary and multilocational research, and needs to be stored and managed efficiently. Field research, even at the individual level, involves recording data in a number of experimental plots or farmers’ fields and over several seasons. DBMS enable such research data to be organized and managed efficiently both at the individual and multiuser level for purposes of analysis, decision-making and presentations.. Further, the users of the research data can be diverse and not limited to those who generated the data. Researchers like those involved in developing simulation models for decision support, technology transfer or in designing agricultural policy and development programmes often use data generated from others’ research to save on time and costs. For such users, and also for individual researchers DBMS help to:

• separate data from applications (the need to do this is becoming more and more important in modern research when data have to be shared between diverse users and applications)

• avoid unnecessary duplication of data

• perform two basic functions – reading and editing – on the data routinely and

consistently. Both require systematic and consistent identification of the data. This can be difficult without a DBMS when data are large and complex

• when data are large and complex they need to be carefully structured to identify

specific data and eliminate redundancy and inconsistency in the databases. Database management systems permit this.

Database management concepts are central to the newer tools of agricultural research like GIS (in natural resources management research), and bioinformatics (in plant and animal science research).

Some example areas of agricultural research and policy where databases are useful because of the large variety and complexity of data are:

• Administration and management • Planning and policy • Natural resources management

• Managing coordinated projects

• Genetic resources classification

• Experimental station management

• Bioinformatics/genomics/proteomics Database types The most familiar way of representing data about entities (distinguishable real world objects with common properties; examples of entities are students, employees, states, districts, farmers, field plots, fertilizers, rainfall, etc.) is in the form of Tables or data files Tables are two-dimensional structures consisting of columns and rows. The columns are called Fields and the rows are called records in database terminology. Thus, in a Table, data are stored in fields and records. A field is the basic unit of representing information about an entity. Each field refers to one attribute or property of the entity. For example, ‘name’ is a field or attribute of entity employee in an employee table or data file;, ‘age’ is another such attribute for the same entity; temperature and rainfall are fields/attributes of the entity weather in a weather table or data file; plot no., dates of sowing are fields/attributes of the entity, experimental plot data file; district name, area, etc are data fields corresponding to the entity districts in a districts table or data file and so on. Records are actual data (text, numbers, dates, etc.) for each attribute/field in the Table. Each record is one set of attribute data, that is, the data of all fields for one entity (eg. text, numbers, dates, etc. representing say name, age, date of birth, etc. for any one employee in the employees data file, or soil type, texture, available water capacity etc., in soils data file, district number, name and area in a districts data file, etc.).

Table of Districts

District Area (‘000 ha) Population (000)

Aaaa 2000 25000

Bbbb 3000 23578

Cccc 1500 15789

S

Numbnumb

R

FIELD

In a table each record is one row of data, and fields are the column headings.

Number of fields = number of columns

er of records = er of rows of data

ECORD

Commonly used database structures for organizing data in tables are of two types: • Flat file (one table) • Relational (many tables) Flat File Databases In aflat file database, all the information is in one table of one array of rows and columns like the Table of Districts in the example above. A typical example of a flat file database is a spreadsheet (MS Excel Table) The Advantages of a flat file data structure are that it is simple and easy to implement when the number of records (rows) and attributes (fields) are few. However, if there is repetitive information in the table ( like similar data for different years - see table below) and if there are a large number of attribute data (more columns) the flat file database structure can be unwieldy:

District

Area (‘000 ha)

Population (000)

Year Area_rice (ha) Prod_rice (tonnes)

Aaaa 2000 25000 1990 10000 15000

Aaaa 2000 25000 1991 10500 18000

Aaaa 2000 25000 1992 11000 11900

Bbbb 2500 23578 1990 11235 20345

7

The disadvantages of a flat file data structure are that there can be : • too much information in one table if there are a large number of multiple attribute/

fields data (table width can increase to several screen widths) making it unwieldy • repetitions of data in some columns(redundancy) • difficulties in editing leading to data base errors and inconsistencies

As the

variety of information increases, or if there are multiple entries for any one type ofdata and information needs to be duplicated for some fields, the table (flat file) may grow totoo large a size to facilitate easy retrieval and updating of information. It also becomescumbersome to update the database frequently and errors are likely. Flat file databasestructures are not suitable for such situations.

Relational Databases Relational databases eliminate the problems of redundancy and inconsistency of data encountered in flat file design by splitting data into several tables and establishing relations between them. The splitting of data into several tables is such that each table represents one entity . Intafo

P(wieb

Intaplithtainre

A collection of related tables is a relational database

a relational database, two tables which form relationship are referred to as the primary ble and the related table. The tables can be related if they have a common field. The llowing examples illustrate this.

Employee database

Employees

Pay

Performance

Training

Broad categories/themes ofrelated information about employees / entities – related tables

rimary Tablelist of employees ith basic

nformation of ach as in service ook)

leave

Relational databases – example 1

the above database (example 1), a primary category of data is identified to which other bles or entities can be related. In example 1, which deals with data about employees, the rimary table will hold basic information about individual employees. It will contain fields ke EmployeeID, Name, Date of Birth, etc. The number of records in this Table will equal e number of employees. The related Tables will hold data about employees. Each related ble holds data of one category or theme represented by different fields (Basic pay, DA, Etc., Pay Table; Type of leave, from and to dates, etc. in the Leave Table and so on. Each of the lated Tables will also have a common field with the primary table to connect the data in it

to individual employees.. This field is usually the EmployeeID field. Using this common field, the data in all the Tables can be connected to create useful information like salary slips, leave and performance reports, etc., for the employees.

Districtfruits

Cerealsvegetables

Fertilizer use

Weather

Livestock

Agricultural production and resources database of districts

Primary Table (list of districts)

Entities/Related Tables with annual data for districts

Relational databases – example 2

In example 2, the Primary table, District, holds data about the districts by using data fields like DISTID, Name, Area, etc. The related tables hold data for different districts on themes like annual area and production of different cereal crops, fertilizer use etc. The Tables can be related if they have the field DISTID in common with the primary table, District. Once related useful information like crop yield, input and weather variations, etc, across districts can be obtained.

In a relational database:

• Related fields form a Table • Related tables form a database • Records in any two tables can be connected through a common field that appears in

both the tables

The word "relational" is often omitted nowadays, since most well known DBMSs (e.g., MS Access, MS SQL Server, Oracle, Sybase) are RDBMSs. The subsequent discussion will be only about relational databases. Even though there are other database types like hierarchical or network databases, these are not so common any more.

Database structure Relational databases follow well defined rules of structure to maintain data integrity. If the structure design is good, it allows easy modifications and data retrieval, and minimizes scope for data entry errors. Crucial to good design of database structure are the determination of :

(i) (ii) (iii)

Tables and keys Relationships between the tables, and Integrity rules which determine the consistency and efficiency of the database.

Tables and Keys The first step in creating the database structure is to develop a list of all the data fields required for the database and group them into different tables by themes. The grouping should allow identification of the Primary and Related Tables. The tables can be related if they have a common field.

No.

Relating Tables in a database (example 1): Employee data

Table 1-Base data (service book)

Table 2 Pay data

ID Name Division Designation 1001 Aaaa Agronomy Asoc Professor 1002 Bbbb Genetics Professor 1003 Cccc Engineering Asst.Professor

ID Month Basic HRA DA

1 1001 January 10000 1500 4000 2 1001 February 10000 1500 4000 3 1002 January 8000 1200 3200 4 1002 February 8000 1200 3200

In the above example, the two tables Table 1 (primary table) and Table 2 (related table) have a common field ID (Identification number of employee). Records in the two Tables can therefore be connected via this common field. Once connected/related, the two tables can be used to prepare a pay slip for an employee in any month. The pay related data for each employee are drawn from Table 2 and the details of the corresponding employee can be drawn from Table 1 using the common field (ID . Note that in Table 1, the identification number of each employee (ID, First column) is unique to distinguish one employee from another. The data in other fields need not be unique. For example, names of employees can be same for more than one employee and so can the other fields. Each row of data can be located and identified using the ID field. Each table entry

contains only a single value. The order of the rows and columns is not important. They can be viewed or added in any order. The field ID. is called the Primary Key of the Table. In Table 2, records can be uniquely identified by a single field only when the serial number column (No., First column) is included in the table. So, in this table the field NO. is the primary key. The field ID in Table 2 ( which is the common field with Table 1) is called the Foreign Key. Note that in the above tables, the information content of a table does not depend on

• The order of the rows; or • The order of the column

Further, the rows and columns of a table can be rearranged at will without affecting the table's information content) Rel In tfielkey

Primary Key and Foreign Key Primary key is a Field (attribute/column) that uniquely identifies each record in the table NOTE:

• Choice of primary key is usually obvious from the structure of the Table. • If there is no easy natural choice for a primary key add a column containing a

unique identifier (serial number) • Data in every column of the row must be dependent on the primary key

Foreign key is the Field in the related Table that is common with the Primary key in the primary table. The primary key and the foreign key connect the primary and related Tables.

ationships

he above example, in the primary table (Table 1), for every data value in the primary key d (ID) there are several values in the Related Table (Table 2) in the foreign or common field (ID). The two Tables are said to have a one-to-many relationship.

SimprimDISrelaprothe

Types of Relationships A Relationship is created between two tables by creating a join between them through thecommon field. Records between two tables are then connected through the commonfield. Creating the relationship allows viewing and extracting data from the two differenttables as if they were from one large table.

(i) A one-to-many relationship exists between two tables when one record in theprimry table matches zero, one or many records in the related table.

(ii) Many-to-many relationships can also occur. In such relationships, each recordin the primary table can have many matching records in the related table andone record in the related table has many matching records in the primarytable.

ilarly in the districts database in the following example, DISTID is the primary key in the ary table and the serial number field (NO). Is the primary key in the two related tables.

TID is the foreign key in the related tables. The primary and the related tables 1 and 2 are ted by a one-to-many relationship. The three tables can be used to relate the cereals duction and fertilizer use in any district and year as the field DISTID is common between m.

Basic data of districts – Primary table

Area and production of cereals – Related Table 1

Fertilizer use – Related Table 2

Relating Tables in a databases (example 2): Database of agricultural production and resources in districts

DISTID Distname Statename 1001 aaaaa bbbbb

NO DISTID Year Rice_ka Rice_kp Wheat_a Whep

1 1001 1990 RA1 RP1 WA! WA22 1001 1991 RA2 RP2

NO DISTID Year N P K 1 1001 1990 N1 P1 K1 2 1001 1991 N2

Database integrity In a relational database, integrity must be maintained between data in the primary and related tables. This implies that:

(i) There cannot be any values in the foreign key field of the related table, corresponding values for which do not exist in the primary table.

(ii) Any editorial changes to the data values in the primary key field of the primary table must be automatically reflected in the corresponding data values in the foreign key field of the related table. The user should not have to reopen each related table to make the required changes in the foreign key field.

(iii) If one record is deleted from the primary table, then all the records in the related tables with corresponding data in the foreign key field should be deleted automatically.

All of these essentially mean that that there must be consistency between data in the primary and related tables to maintain valid relationships. For such consistency the data must follow specific rules called data integrity rules.

Database Integrity Rules

(i) in all tables the primary key must be unique and that there should be no null values in this field. (primary key integrity)

(ii) each non-null foreign key value in the related table must match a corresponding primary key value in the primary table (referential integrity)

(iii) the data types of primary and foreign key in a the primary and related tables must match perfectly (domain integrity)

Summary of database design

Designing the database structure – summary of steps

• Identify all relevant entities (Tables) and attributes of each entity (fields) required to produce the needed information

• Group related fields into tables (one table for one theme or set of related fields) • Determine the relationships between the tables. (primary and related tables) • Determine the properties of each field (field name, data type, description, etc.) • Determine the primary key of each table - unique identifier for a row • Include a common field with the primary table in the related tables • Avoid data redundancy in all tables:

No table must have duplicate rows or columns No duplication of data between tables No derived or calculated data fields Eliminate columns that do not depend on the primary key Create new tables if necessary

• Identify the common field between the Primary and related tables. This is usually the

primary key in the Primary Table. The same (common) field in the related table is called the Foreign key

• Ensure that the data types of the primary and foreign key are the same. • Connect the tables by joining the primary key from primary table with foreign key of

related table to create relationships. • Add data to tables

Database management system (DBMS)

The database tables, keys and relationships (which constitute the structure of the database) and the software that facilitates their creation, storage, retrieval and linkages, together constitute a database management system. A DBMS may also be called a database management programme. MS Access is one such database management programme, that is powerful, efficient and flexible enough for developing information systems for a range of purposes. In addition to storing and arranging information Access helps to run reports that lead to conclusions. Using Access, data can be entered directly into a database or imported from another programme, sorted, indexed and organized in whichever way needed, and reports can be created quickly using all or part of the data. It is possible to customize data entry into simple filling the blanks on a form and also run queries that extract subsets of the data that meet specified conditions. MS Access terminology

MS Access is an object-oriented programme; that is everything in Access is an object, including the database application itself. All objects of the database are stored in a single data file, and the filename has an .MDB extension. The objects are managed through a Database window. An important feature of Access is that it comes with several database wizards. These are mini programmes that interact with the user about his needs for creating different objects, and then create the database structures that match them. The user only needs to choose among a range of options and enter the actual data. Excellent help are also features available in MS Access for users to learn and deploy the various functions. Because of such user-friendly tools for designing each object, Access is an appropriate database management tool for both novices and professionals.

The first step in developing a DBMS using Access is the creation of the database file. This file contains all the data in the form of several tables. It also contains files for customized data entry forms, reports and queries that constitute the database application. Thus a database file in Access contains files which can be: Tables, Forms, Queries or Reports

Tables are the core primary building blocks of a database. A Table is very much like

a data table or spreadsheet containing rows (records) arranged in different columns (fields). At the intersection of field and a row is the individual bit of data for a particular record, called a cell. Each database file can have many tables. Each Table is collection of similar data. All the data entered into a database end up in a Table for storage. The specific Tables into which the data will be organized needs to be planned carefully and frequent changes in their form and structure should be avoided. Information can be entered directly into each Table, but this may prove cumbersome if there are too many columns and rows. In such case forms are used to enter data by records.

Forms are a more convenient means of data entry and viewing. In Access, a fill-in-the-blanks kind a form (similar to an application form) can be created to simplify data entry. Data entered in a Form gets stored in a specified row in a Table, as Access automatically links them. One convenient feature is that separate forms need not be created for filling each Table. A single form can be used to enter data into several Tables at the same time. It can therefore serve as link between Tables. Forms are designed to be used on screen for data

entry based on the needs and some flexibility in their changes is possible, but it is better to plan them in advance.

Queries are questions that users ask of the data stored in the Tables to obtain information. They facilitate seeing data from several Tables simultaneously. They also facilitate seeing only that part of the data in the Tables that is desired at a particular time by filtering out the data that may not be needed.

Reports are designed to be printed. They are specially formatted collections of data, organized in a specified way to summarize the data. A report can extract data from many Tables, perform simple calculations on the data and present results in a neat format. Reports can be created at any time. They need not always be planned beforehand.

Tables, forms, reports and queries are created in separate steps, but they are related. Tables are the core of the DBMS, with the others having to do with entering, extracting or presenting the data in the Tables.

Multiple Tables can be created in Access to reduce redundancy in a database. By creating Forms, Queries and Reports, data can be extracted from more than one Table easily. This can be done best when there is a well-defined relationship between the Tables. When two Tables have a common field they can be related. Defining relationships: A relationship is defined in MS Access by adding the tables to be related to the Relationships window, and then dragging the key field from the primary table and dropping it on the key field in the other table. The kind of relationship that Microsoft Access creates depends on how the related fields are defined: - A one-to-one relationship is created if the related fields are both primary keys. - A one-to-many relationship is created if the related fields are a primary key and a

foreign key. The accompanying chart shows the type of relationships that can be established in an

national level district wise agricultural resources database. Notice the 1 and infinity sign next to the primary key and foreign key (DIST). This implies a one-to-many relationship between the two tables. The signs appear in relationships whenever ‘referential integrity’ (another feature of MS Access) is enforced in relationships. Enforcing referential integrity prevents data entry mistakes and ensures that information in the two field’s matches.

Fig1. Tables and their linkages in a district database

Using the above Tables, forms (Fig 2) reports can be generated from queries for specific information about say the average irrigated area under rice in past five years in each district of a State (Fig 3) or the rice yield variations during kahrif and rabi and the corresponding variations in rainfall and fertilizer use during the past five years (Fig 4).

Fig 2: Form for entering data of rice

Irrigated area under crops

DISTRICT RICE CEREALS PULSES OILSEEDS SUGARCANE COTTON

Chengalpattu Summ or 'DIST' = 83 (4 detail records) ary f Avg. 229.0475 234.3175 5.87 60.12 13.715 0.09 South Arcot Sum ary for 'DIST' = 84 (4 detail records) mAvg. 187.54 192.9575 0.7425 52.95 48.6175 8.0225 North Arcot Sum ary for 'DIST' = 85 (4 detail records) mAvg. 78.935 59.9025 1.4275 27.84 21.5425 0.99 Salem Sum ary for 'DIST' = 86 (4 detail records) mAvg. 55.4475 82.475 12.075 41.7 16.0675 8.095 Coimbatore Sum ary for 'DIST' = 87 (4 detail records) mAvg. 21.455 39.625 2.2625 69.2275 11.93 10.9875 Tiruchirapalli Sum ary for 'DIST' = 88 (4 detail records) mAvg. 109.915 114.5825 2.875 26.625 22.0125 2.23 Tanjavur Sum ary for 'DIST' = 89 (4 detail records) mAvg. 333.0625 333.535 3.97 14.13 16.9275 3.815 Madurai Sum ary for 'DIST' = 90 (4 detail records) mAvg. 113.185 120.0975 3.7675 68.3175 14.7675 12.05 Ramanthapura Sum ary for 'DIST' = 91 (4 detail records) mAvg. 59.6575 60.5025 0.0725 4.535 0.0975 0.4525 Tirunelveli Sum ary for 'DIST' = 92 (4 detail records) mAvg. 101.5875 105.815 2.375 14.3725 4.1675 9.3225 The Nilgiris Sum ary for 'DIST' = 93 (4 de ail records) m tAvg. 0.14 0.1425 0 0.135 0.0025 0.0025 Kanyayakumari

Fig.3 Part of sample report for irrigated areas in districts of Tamilnadu.

Fig 4. Rice yields, rainfall and fertilizer use in Tanjavur district of Tamil Nadu

Case study Objective: To design a prototype district level Rice Production Information System (RPIS) for Andhra Pradesh using MS Access. The DBMS should facilitate sorting and filtering data by district, region, years and also allow queries on variations in rice yields. It should also contain appropriate Forms for entering data in the available formats, and Reports and graphs for presenting the results of analysis. Given:

(i) List of districts (ii) Data sheet of rice production during 1993-97 (iii) Data sheet of rice area during 1993-97

Step 1: Conceptual design of database structure (identification of tables, keys, relationships) (a) List all the fields of interest and identify their data types The fields are (i) DISTID (identification number of district - integer) (ii) DISTNAME (name of district - character) (iii) YEAR (integer) (iv) RICEKA ( area under rice in kharif season - number) (v) RICERA ( area under rice in rabi season - number) (vi) RICEKP (production of rice in kharif season- number) (vii) RICERP (production of rice in rabi season - number) (b) Group data fields into tables by theme Two tables will be required based on the two themes of data – districts, area and production of rice. Table 1 will be the the districts table and will contain the fields DISTID and DISTNAME. Table 2 will be the area and production of rice table and contain the fields DISTID, YEAR, RICEKA, RICERA, RICEKP and RICERP. DISTID will be the common field between the two tables (c) Identify primary and related tables Since the area and production of rice data is data is about districts, the primary table will be Table1 Table 2 will be the related table containing information about area and production of rice in districts in different years

(d) Identify the keys in each table and the relationships In table 1, since DISTID takes unique values and identifies each row uniquely it is the primary key in table 1. In Table 2, none of the listed fields will take on unique values and can therefore be a primary key. With the existing set of fields it will not be possible to uniquely identify a record. So, a new field (serial Number, NO) is introduced to be the primary key. DISTID which is the common field between Table 1 and Table 2 can be used to connect or relate the records in the two tables. The relationship between the two tables can be established by connecting DISTID in Table 1 with DISTID in Table 2. When this is done DISTID becomes the foreign key in Table 2. Step 2: Create the database file in MS Access

(i) Start Access from START menu on task bar of Windows or from MS Office Shortcut toll bar.

(ii) Create a blank database by selecting the NEW DATABASE option on FILE menu.

(iii) In the dialogue box that is displayed select BLANK DATABASE and Click OK. (iv) The database window is displayed (v) Specify the file name in the dialogue box as APRICE. This file is saved with a

.MDB extension is APRICE.MDB. Note that the file name appears on the database window.

Step 3. Create tables (a) Table 1: Design and create the following Table with DISTID and DISTNAME as two fields. The data type of DISTID is number (integer) and of DISTNAME is text. Make DISTID the primary key field. In the database window, select TABLES on the bar. Since this is a new database, the window that appears is blank. (For an existing database, the created objects will be displayed). Of the 3 buttons on the right side of the Window, select OPEN : for viewing the selected object (TABLE) in an existing database DESIGN : for opening the object the design mode to make any changes to the

structure of the TABLE, or NEW : for creating a new object (TABLE) Select New to create a new Table In the dialogue box that appears, select Design View This displays the Table in the design view to define the fields and their properties. Create the Table using Design view by typing in each row the Field Name , Data Type and Description

for the Fieldthat is to be created. (Data types can be Text, Memo, Number, Date, Currency, Auto number, Yes / No etc.). For Table 1, Row 1 will be DISTID (data type integer) and Row 2 DISTNAME (data type – character). Descriptions about the fileds can be filled in their respective rows. (Giving description is optional. Users normally would expand the code, give the units of data, source etc., in the column for Description) Then for the Field to be designated as the Primary Key (DISTID), Click on the extreme left of its row. The row is highlighted. Select the Edit menu option from the top bar and select Primary Key. A key symbol appears on the left side of the selected field. (Alternately the primary key selection tool is also available on the MS Access tool bar and can be clicked directly) Save the Table with the name APDISTRICTS. The Table APDISTRICTS is now listed in the database window. Select DISTRICTS and select view in the Top bar and select Datasheet View. The table is displayed with a blank row. (Alternately double clicking on DISTRICTS in database window also opens the table with the blank row. Data can be typed into each column of this row (or previously existing data can be edited). Records can be sorted in ascending or descending order for each column after they are entered. Specific records can be selected from the record toolbar that is displayed at the bottom of the Table. Columns can be moved or resized by selecting the fields and dragging them to be desired location. Columns can also be hidden if required. Open the Table and enter the data directly on screen as shown below for DISTID and DISTNAME. DISTID DISTNAME 101 Srikakulam 102 Vizianagaram 103 Visakhapatnam 104 East Godavari 105 West Godavari 106 Krishna 107 Guntur 108 Prakasam 109 Nellore 110 Kurnool 111 Ananthapur 112 Cuddapah 113 Chittoor 114 Rangareddy 115 Nizamabad 116 Medak 117 Mahbubnagar 118 Nalgonda 119 Warangal 120 Khammam 121 Karimnagar 122 Adilabad Note DISTIDs 1-9 represent Coastal Andhra Region 10-13 represent Rayalaseema region 14-22 represent Telangana region

(b) Table 2: Design the second table for data of annual rice area and production in kharif and rabi seasons by following the same procedure as for Table 1. The table will have the following fields NO, DISTID, YEAR, RICEKA, RICEKP, RICERA, and RICERP NO will be the primary key field. Choose the data type of this as Autonumber. Choose data type of all other fields is number. Save this Table with the name APRICE (Note: RICEKA= Area under rice in Kharif; RICEKP= Production of rice in Kharif RICERA= Area under rice in Rabi; RICERP= Production of rice in rabi) Since this is a wide and long table, it would be convenient to enter data through forms (see step 5) Step 4: Creating relationships To create the relationships between the two tables APDISTRICTS and APRICE in the database, select RELATIONSHIP option from the TOOLS menu (or from the Access Tool bar). A Relationships window appears on the computer screen. When this is done for the first time, the Show table dialogue box also appears with a drop down list of the Tables that have been created. At other times the dialog box has to be invoked by selecting ‘Show Table’ from the TOOL bar. Select the Tables that are to be related (APDISTRICTS and APRICE) by double clicking on drop down list. After selecting the Tables click the close button of the Show Table box. For each table that is selected, a Table field box is displayed in the Relationships window. The box displays a list of the fields in each table. The primary key of each Table will be in bold letters. Select and Drag the primary key of the primary Table (DISTID in APDISTRICTS) to the foreign key (variable with the same name as primary Key) of the related Table (DISTID in APRICE). A relationships detail window appears. The window displays the names of the related fields and their respective tables. Click on Enforce Referential Integrity, Cascade update Related Fields and Cascade Relate Deleted fields to ensure that : 1. For every record in the foreign key field in the related Table, a corresponding record

exists in primary key field in the primary table. 2. Changes made to primary key, are automatically made for the foreign key, and 3. Whenever a record in the primary key field is deleted, all corresponding records in

the foreign key field of the related table are also deleted automatically. (This ensures that referential integrity is enforced between the primary key and foreign key) Click on CREATE. The relationships window reappears with the field boxes of the related TABLES. A line joining the primary and foreign keys is seen with the 1 and infinity signs or 1 and 1 signs at either and depending on whether the relationship is one-to-one or one-to-many. Step 5: Creating forms Create the following two forms for entering data of area and production of rice, FORM1 for production data ( please see data sheet 1) and

FORM2 for Area data (Please see Data sheet 2). Note that data from both forms will be entered into Table 2, APRICE Click on the FORMS tab in the Database Window. The Forms window appears with the three buttons, OPEN, DESIGN, NEW, just as in the case of Tables. If there are any old forms created these will also be displayed. Otherwise, the window is blank. To create a new form, first click on NEW. A new form dialog box is displayed. Select FORM WIZARD and keep answering the dialogue boxes that appear. The first dialog box asks questions about the Tables that are to be selected and the fields from each selected Table that need to be included in the form. To create FORM1 – Production Form,

(i) select APDISTRICTS from the Table list down menu on the form wizard. The efields of this Table (DISTID and DISTNAME) appear in the ‘Available Fields’ box below the selected Table.

(ii) Select the field DISTID from the ‘Available fields’ box and click on the > button to transfer it to the ‘Selected Fields ‘ box for the form.

(iii) Similarly select the Field DISTNAME from the available fields box and transfer it to the selected fields box.

(iv) Select the second table, APRICE. The fields of this table (NO,DISTID,YEAR, RICEKA,RICERA,RICEKP, RICERP) appear in the available fields box.

(v) Since FORM1 is for production data, select successively the fields YEAR, RICEKP and RICERP in the available fields box and transfer them to the selected fileds box as in (ii) and (iii) above

(vi) Click on the Next button and select the form layout (vii) Click on Next button and enter the form name, PRODUCTION FORM. (viii) At the last dialogue box, click Finish..

To create Form 2 – AREA FORM: Repeat (i) to (viii) above with the exception that at Step v select YEAR, RICEKA and RICERA and in step vii name the form ARE FORM. Step 6: Entering data (i) Enter production data into table 2 (APRICE) from datasheet 1 using PRODUCTION

DATA form (FORM1) (ii) Enter area data into table 2 (APRICE) from datasheet 2 using AREA DATA form

(FORM2) Step 7: Create a query to obtain rice yields and sort by district Let rice yield in kharif season be represented by RICEKY and in rabi season by RICERY.

(Queries are also Tables, with the difference that they are in response to questions asked of the data in the Tables. But unlike in Tables, the tables that are seen on the screen are not stored. What is stored is the question or the query. Each time the query is invoked, it is run and the output is seen as a table on the screen.)

(i) Select QUERY tab on the database window, and select NEW for a new query. The new query dialogue box appears.

(ii) Select Simple Query Wizard (iii) Select Tables and fields options (DISTID and DISTNAME from APDISTRITS

table and YEAR, RICEKA, RICEKP, RICE KA and RICERA from APRICE table.

(iv) Assign the query a name (riceyield query) as in the case of FORMS above. (v) In the databse window, open the query. A table with data in selected fields

appears. (vi) Select design view in the query window, for setting criteria, sorting records and

inserting new fields (rice yields RICEKY and RICERY) that are derived from the selected fields by calculations.

(vii) Create new fields RICEKY ( for rice yield in kharif) and RICERY (rice yield in rabi) in the Fields row of the query design view as:

RICEKY: [RICEKP]/[RICEKA] RICERY: [RICERP]/[RICERA]

(viii) Create a parametric query to display information by district name. To do this, in the query design view, in the criteria row and field DISTNAME type: [ENTER DISTNAME]

Save and open query to display result. The query will prompt the user for the name of the district and output the data of the selected fields for the district

Step8: Prepare reports Prepare a chart showing rice kharif and rabi productivity trend by district(Yield vs year) the results of the query: Select Reports button in database window, select new, select chart wizard, select the query and fields and follow the instructions as they appear just as in the case of forms and queries. Additional exercise: Prepare Reports summarizing the production in

(a) Coastal Andhra (DIST 1-9) (b) Rayalaseema (DIST 10-13) (c) Telangana (DIST 14-22)

DATA SHEET 1

Rice Production in Andhra Pradesh from1993 to 1997

1993 1994 1995 1996 1997No.

District

Kharif Rabi Kharif Rabi Kharif Rabi Kharif Rabi Kharif Rabi1. Srikakulam 387 4 388 4 412 5 327 3 278 32. Vijayanagaram 195 6 231 3 319 5 297 4 186 33. Visakhpatnam 104 9 121 9 204 10 197 13 80 94. East Godavari 921 590 544 461 577 563 402 615 429 4925. West Godavari 671 695 709 733 591 666 376 759 630 6736. Krishna 731 365 738 386 644 346 797 100 699 3947. Guntur 960 14 755 48 825 17 928 20 845 528. Prakasham 278 118 165 166 149 83 224 186 124 2229. Nellore 112 557 133 473 190 302 159 472 128 542COSTAL ANDHRA 4059 2358 3784 2283 3911 1997 3705 2472 3399 239710. Kurnool 180 12 108 31 163 24 217 36 177 2411. Anathapur 54 53 39 33 64 25 96 72 25 3712. Cuddapah 140 30 107 35 135 28 162 38 78 2713. Chittor 75 178 67 118 91 91 147 176 85 137RAYALASEEMA 449 303 321 217 453 168 622 322 415 22514. Rangareddy 56 32 50 31 47 35 58 52 49 4315. Nizamabad 200 26 220 35 206 84 270 107 135 4916. Medak 136 28 117 64 111 78 143 76 83 5217. Mahbubnagar 73 53 76 45 102 89 176 90 101 7818. Nalgonda 420 227 369 280 346 166 475 300 370 15019. Warangla 219 50 290 89 226 96 360 119 97 8320. Khammam 329 34 409 43 272 32 428 48 252 1721. Karminagar 281 99 246 191 260 252 379 129 289 38822. Adilabad 124 6 107 10 64 19 129 16 29 12

DATA SHEET 2

Rice area in Andhra Pradesh from1993 to 1997

1993 1994 1995 1996 1997No.

District

Kharif Rabi Kharif Rabi Kharif Rabi Kharif Rabi Kharif Rabi1. Srikakulam 191 1 205 2 219 2 183 1 186 12. Vijayanagaram 111 2 129 1 136 2 131 1 130 13. Visakhpatnam 95 3 101 3 115 4 114 4 96 34. East Godavari 237 158 243 157 260 158 262 160 214 1545. West Godavari 235 188 264 197 270 198 269 199 247 1936. Krishna 255 117 275 122 260 108 279 111 258 1167. Guntur 291 5 288 17 273 6 292 6 295 148. Prakasham 93 41 71 64 60 47 78 62 62 749. Nellore 42 184 49 161 71 143 57 170 49 18210. Kurnool 67 6 50 14 65 8 69 15 66 911. Anathapur 24 25 19 17 27 14 37 31 36 1812. Cuddapah 45 20 38 13 47 12 35 17 48 1313. Chittor 36 70 34 48 38 45 58 75 42 5714. Rangareddy 26 13 22 13 22 18 27 21 24 1615. Nizamabad 99 12 94 16 102 34 106 42 82 2116. Medak 72 20 54 27 64 41 68 40 48 2617. Mahbubnagar 43 32 41 28 54 46 76 47 53 3618. Nalgonda 133 92 125 102 130 66 159 120 149 6319. Warangla 86 22 104 38 94 42 1360 49 43 3520. Khammam 130 15 154 17 116 13 164 19 121 921. Karminagar 105 43 92 66 104 88 125 105 103 3822. Adilabad 59 3 58 4 63 7 58 6 31 5