A database is a collection of information organized so that it can be readily accessed using a computer. Databases in MapInfo Pro are often referred to as tables. MapInfo Pro creates a visual display of the data in tables in the form of a map.
Emergency medical calls thematically shaded by type of call and time of call, with response zones shaded by number of calls.
To understand MapInfo Pro, you need a basic understanding of database organization, in particular, three fundamental concepts: record, field, index, and query.
| LastName | FirstName | Address | ZIPCode |
|---|---|---|---|
|
Fraser |
Mark |
212 Hudson St |
12205 |
|
Donaldson |
Eva |
459 Yates St |
12208 |
|
Espinosa |
Kim |
200 Broadway |
12180 |
|
Smith |
Charles |
1 Redbird Ln |
12065 |
|
Chang |
Elizabeth |
53 Crescent Rd |
12077 |
To understand the database concepts we are about to discuss, consider the table above.
Each row in the list contains information about one person. In database terms, each row is a record. Each different box of information (Last Name, First Name, etc.) within a record is called a field. Fields correspond to the columns so that the table shown above contains four different fields.
Database fields are ordered (first, second, third, fourth, etc.), and the basic convention is that the first field displays as the first column in the database. The second field is in the column to the right of the first, and so on to the last field, which is displayed in the right most column.
Since the data in a database is not usually in alphabetical order or postal code order or any other pattern which would make it easy for the computer to find the information, the computer needs a way to organize the information. A database uses an index to keep track of what information is where and what record it is tied to. Without indices it would be tedious to find anything in a database with hundreds of records, not to mention databases with thousands and tens of thousands of records.
A database index works on the same principle as a book index. A book index is an alphabetical list of topics that appear in the book and the page number or address of the information. Database indices work in a similar way, except that they generally work behind the scenes. You do not ever see them. But the computer constructs them and allows you to use them in your work. An index allows the computer to work with the records according to the order of items in the key field.
MapInfo Pro requires fields to be indexed in order to use the Find command. Indices are also used to improve performance in SQL Select and joins.
A query is just another word for a question. You query data to collect a particular type of information from your database. For example, if you wanted to know how many customers live within a certain number of miles of your store, (and you had that kind of information in your database), you could query the database to find out that information. The result of the query is query data. You can think of query data as a subset of your data as in the example - a list of all the customers within 5 miles and none of the customers who live further away. MapInfo Pro has commands to help you query your data and display it on a map.
For more about querying your data, see Selecting and Querying Data.
For more about querying your data, see Selecting and Querying Data in the Help System.