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Creating Fields
Administrator
4. From the Machine Data Source tab, select the
ODBC data source to access, and then click
OK.
NOTE: The ODBC data source dialog box shows all
data sources known to ODBC, including ChemFinder,
Access, and other file-based data sources. If you attempt
to open one of these through the ODBC dialog, you get
an error message. File-based data sources must be
opened using Open Database, as described above.
Whether you created a new database or are working
in an existing one, you can add or remove fields in
the selected table.
You can choose from the following types of fields:
Text field—Allows you to enter text such as
names, comments, and references. A text field is
fixed in length, and requires that you choose a
maximum length (“width”) for any data item to be
stored in the field. If you enter a width of 50, then
you can’t store any item with more than 50
characters in that field.
You can specify widths of text fields as large as 254
characters. If this is insufficient, you need to create
a Memo/Rich Text field instead.
Because the text field width cannot be modified
after a field is created, it is often wise to err on the
side of caution and make it longer than you need
initially. On the other hand, larger field widths also
create larger files and slower search times.
NOTE: If the ODBC data source dialog does not
show the database you seek, you may need to create a
new data source. You can do this using the New button.
For details, click the Help button in the ODBC dialog
box.
5. If you are prompted for a user name and
password, enter it. If you don't know what
name and password to use, see your System
Administrator.
6. Click on the name of the table you want to
attach, then click OK.
The source of the data to display on the form is
indicated, but the form is still blank. To access the
data, you need to draw some data boxes, and
indicate what data to show in each of those boxes.
NOTE: Non-ASCII characters will not display correctly
in a data table text field.
Integer field—Used for whole numbers such
as ID's. All integers in ChemFinder are long, so can
accommodate billions of values (2 32 of them).
Double field—Used for real numbers such as
physical constants and unit prices. Real numbers in
ChemFinder are double-precision.
Picture field—Allows you to store a Windows
metafile, such as a spectrum or experimental setup,
as a data item in a database.
NOTE: A Picture box on a form may be used to display a
static, decorative picture attached to the form, or it may be
used to show pictures stored in the database which change as
you move from record to record.
290•Working with Data
CambridgeSoft
Creating a Database