ch02.htm

Microsoft_Access_97_Quick_Reference.zip

				<P>
				<DD><B>2. </B>Click in the field you want to remove and click the Delete Rows button
				on the toolbar.
				<P>
				<DD><B>3. </B>When prompted if you want to permanently delete the information, choose
				<U>Y</U>es (but only if you really want to).
			</DL>
			<H2><FONT COLOR="#000077"><B>Field: Description</B></FONT></H2>
			<P>The Description <I>property</I> provides information or notes about fields in
			tables, and queries. Descriptions can be up to 255 characters in length. Descriptions
			appear in the <I>status bar</I> while entering data in a <I>field</I> in Datasheet
			or <I>Form View</I>.</P>
			<P>This propertyx2 is set in the Table <I>Design View</I> for tables, and in the
			Field Properties Property sheet in the <I>Query</I> window for queries. (See &quot;Queries
			and Filters: Query: Properties&quot; in the Queries and Filters part of this book.)</P>
			<P>When you create a control by dragging a field from a Field List, Access copies
			the Description property to the control's Status Bar Text property. It then displays
			that description in the status bar whenever the <I>insertion point</I> is entered
			into that field.
			<H3><FONT COLOR="#000077"><B>Steps</B></FONT></H3>
			<DL>
				<DD><B>1. </B>Click a table name in the Tables tab of the <I>Database window</I>,
				then choose the <U>D</U>esign button.
				<P>
				<DD><B>2. </B>Click in the Description column of the field.
				<P>
				<DD><B>3. </B>Enter a value for the description. You do not need to surround the
				description with quotation marks.
				<P>
				<DD><B>4. </B>Click the Save button on the toolbar to save your description.
			</DL>
			<H2><FONT COLOR="#000077"><B>Field: Insert</B></FONT></H2>
			<P>You can add a <I>field</I> at the bottom of the field names section <I>Table</I>
			Design window (see &quot;Field: Create&quot;) or you can insert a field in between
			existing fields.
			<H3><FONT COLOR="#000077"><B>Steps</B></FONT></H3>
			<DL>
				<DD><B>1.</B> Click a table name in the Tables tab of the <I>Database window</I>,
				then choose the <U>D</U>esign button.
				<P>
				<DD><B>2. </B>Click in the field below where you want your new field to go and click
				the Insert Rows button on the toolbar.
				<P>
				<DD><B>3. </B>Enter the field name, <I>data type</I>, description, and any properties
				for the field in the field properties section at the bottom of the Table window.
				<P>
				<DD><B>4. </B>Click the Close (X) button on the Table Design window and choose <U>Y</U>es
				to save the changes to the table design.
			</DL>
			<H2><FONT COLOR="#000077"><B>Field: Name</B></FONT></H2>
			<P>You can change the name of a field in your database and your table's data is left
			unaffected. However, if you have used the field in a <I>query</I>, <I>form</I>, or
			<I>report</I> created prior to the change, you must manually update that control
			to reflect the new field name. If you want to see a different name in the column
			header of <I>Datasheet View</I>, you can also change the <I>caption</I> <I>property.</I>
			(See &quot;Fields: Caption as Alternate Name.&quot;)


			<BLOCKQUOTE>
			<P>
<HR>
<FONT COLOR="#000077"><B>NOTE:</B></FONT><B> </B>Field names can be up to 64 characters
			and include spaces. However, if you are going to upsize your database to a database
			<I>server</I> such as <I>SQL</I>, it is better not to include spaces because the
			table's field name spaces will be converted to underscores. Any queries, forms, or
			reports based on the tables will produce errors and will need to be modified. 
<HR>


			</BLOCKQUOTE>

			<H3><FONT COLOR="#000077"><B>Steps</B></FONT></H3>
			<DL>
				<DD><B>1. </B>Click a table name in the Tables tab of the <I>Database window</I>,
				then choose the <U>D</U>esign button.
				<P>
				<DD><B>2.</B> Click the name of the field and edit that name.
				<P>
				<DD><B>3. </B>Click the Close (X) button on the Table Design window and choose <U>Y</U>es
				to save the changes to the table design.
			</DL>
			<H2><FONT COLOR="#000077"><B>Field: Rename in Datasheet View</B></FONT></H2>
			<P>To rename the <I>field</I> in a <I>query</I>, change the name of the field in
			the Query Design <I>grid</I>. That new name provides the column name for the field
			in <I>Datasheet View</I>, unless the <I>Caption</I> <I>property</I> has been set
			(in which case, the caption is used). The renamed field also provides the name of
			the Control Source for any <I>control</I> in a <I>form</I> or <I>report</I> that
			is based on that query.
			<H3><FONT COLOR="#000077"><B>Steps</B></FONT></H3>
			<DL>
				<DD><B>1. </B>Open the <I>table</I> in Datasheet View.
				<P>
				<DD><B>2. </B>Double-click the column header of the field of interest and enter the
				new name of the field.
			</DL>
			<H2><FONT COLOR="#000077"><B>Field: Set Properties</B></FONT></H2>
			<P>You can set many of the field properties in Table <I>Design View</I>. Properties
			include name, <I>data type</I>, description, field length, <I>validation</I> rules,
			default values, and whatever you see on the General or <I>Lookup</I> tabs in table
			design.
			<H3><FONT COLOR="#000077"><B>Steps</B></FONT></H3>
			<DL>
				<DD><B>1. </B>Click a table name in the Tables tab of the <I>Database window</I>,
				then choose the <U>D</U>esign button.
				<P>
				<DD><B>2. </B>Click the field in the Table Design View.
				<P>
				<DD><B>3. </B>Change the properties on the same row of the field name or press F6
				and change the properties in the lower half of the window. The properties include
				field size, format, decimal places, caption, and default value among others. The
				actual properties change depending on the data type. For a description of each property,
				see the blue text on the right or click in the property and press F1.
				<P>
				<DD><B>4. </B>Click the Close (X) button on the Table Design window and choose <U>Y</U>es
				to save the changes to the table design.
			</DL>
			<P>When you click in the text box for some of the <I>properties</I>, there is a drop-down
			arrow representing a list of choices. Click the arrow and then the desired item in
			the list. Some properties (for example, Input Mask) also have a build button (...)
			on the right side of the <I>text box</I>. You can click this or the Build button
			on the toolbar to bring up a dialog box with examples. Another option is to begin
			typing in the text box. Access will automatically complete the entry with the first
			available option where the first letter matches your entry. For example, in the data
			type text box, type <B>n</B> to select number.


			<BLOCKQUOTE>
			<P>
<HR>
<FONT COLOR="#000077"><B>TIP:</B></FONT><B> </B>Double-click any property that has
			multiple choices either in the Data Type or lower section of the design window. This
			will cycle through the available list of choices. (This is a general feature of Property
			sheets.) 
<HR>


			</BLOCKQUOTE>

			<H2><FONT COLOR="#000077"><B>Field: Size</B></FONT></H2>
			<P>Field size for text <I>data type</I> fields determines the maximum number of characters
			you can enter for a <I>field</I>. You can set the field size for text up to 255 characters
			and the default is 50 characters unless you change the default. (See &quot;Data Types:
			Setting Defaults.&quot;)</P>
			<P>For numbers, field size determines the range of numbers you can enter and whether
			or not the number can include decimal places. Generally, you want to set the smallest
			possible field size for text or number but still include all possibilities you might
			enter. With smaller field sizes, your database file will be smaller and quicker.
			<H3><FONT COLOR="#000077"><B>Steps</B></FONT></H3>
			<DL>
				<DD><B>1. </B>Click a <I>table</I> name in the Tables tab of the <I>Database window</I>,
				then choose the <U>D</U>esign button.
				<P>
				<DD><B>2. </B>Click in the field and then click in the Field Size box.
				<P>
				<DD><B>3. </B>Type in a number from 1 to 255 for text data types. If your data type
				is numeric, choose one of the field sizes shown in the following table from the drop-down
				list.
				<P>
				<DD><B>4. </B>Click the Close (X) button on the Table Design window and choose <U>Y</U>es
				to save the changes to the table design.
			</DL>
			<P>You want to choose one of the following numeric field sizes that will accommodate
			your data using the smallest number of bytes possible.
			<H4><FONT COLOR="#000077"><B>Numeric Field Sizes</B></FONT></H4>
			<P>
			<TABLE BORDER="0">
				<TR ALIGN="LEFT" rowspan="1">
					<TD ALIGN="LEFT"><B>Option</B></TD>
					<TD ALIGN="LEFT"><B>Description</B></TD>
					<TD ALIGN="LEFT"><B>Byte Size</B></TD>
				</TR>
				<TR ALIGN="LEFT" rowspan="1">
					<TD ALIGN="LEFT">Byte</TD>
					<TD ALIGN="LEFT">Numbers 0-255 without decimals</TD>
					<TD ALIGN="LEFT">1</TD>
				</TR>
				<TR ALIGN="LEFT" rowspan="1">
					<TD ALIGN="LEFT">Integer</TD>
					<TD ALIGN="LEFT">Numbers from about -32,000 to +32,000 with no decimals</TD>
					<TD ALIGN="LEFT">2</TD>
				</TR>
				<TR ALIGN="LEFT" rowspan="1">
					<TD ALIGN="LEFT">Long Integer</TD>
					<TD ALIGN="LEFT">Very large numbers without decimals (+/- 2 billion)</TD>
					<TD ALIGN="LEFT">4</TD>
				</TR>
				<TR ALIGN="LEFT" rowspan="1">
					<TD ALIGN="LEFT">Single</TD>
					<TD ALIGN="LEFT">Large numbers with decimals (up to 38 digits before or after the decimal place)</TD>
					<TD ALIGN="LEFT">4</TD>
				</TR>
				<TR ALIGN="LEFT" rowspan="1">
					<TD ALIGN="LEFT">Double</TD>
					<TD ALIGN="LEFT">Largest possible numbers with decimals</TD>
					<TD ALIGN="LEFT">8</TD>
				</TR>
			</TABLE>



			<BLOCKQUOTE>
			<P>
<HR>
<FONT COLOR="#000077"><B>NOTE:</B></FONT><B> </B>When you create <I>relationships</I>
			between fields from different tables, all data types and field sizes for numbers
			must match. The exception is an <I>AutoNumber</I> field. Because the <I>foreign key</I>
			field will not be an AutoNumber field, the related field in the second table should
			have Long Integer Field Size. 
<HR>
</P>
			<P>
<HR>
<FONT COLOR="#000077"><B>TIP:</B></FONT><B> </B>If you often calculate with a field
			that has between one and four decimal places, consider using Currency data type instead
			of Single or Double. Currency uses the faster fixed-point calculation rather than
			floating point calculations. 
<HR>


			</BLOCKQUOTE>

			<H2><FONT COLOR="#000077"><B>Gridlines: Turning On and Off</B></FONT></H2>
			<P>Access normally prints and displays vertical and horizontal <I>gridlines</I> in
			<I>Datasheet View</I>. If you want, you can turn these gridlines off. You can also
			change the background or font of the cells. (See &quot;Datasheet: Appearance Change.&quot;)
			<H3><FONT COLOR="#000077"><B>Steps</B></FONT></H3>
			<DL>
				<DD><B>1. </B>Open a <I>table</I>, <I>query</I>, or <I>form</I> in Datasheet View.
				<P>
				<DD><B>2. </B>Choose F<U>o</U>rmat, C<U>e</U>lls.
				<P>
				<DD><B>3. </B>Uncheck one or both of the <U>H</U>orizontal and <U>V</U>ertical <I>check
				boxes</I> in the Gridline Shown section of the Format Cells <I>dialog box</I>; choose
				OK.
			</DL>
			<H2><FONT COLOR="#000077"><B>Hide Column</B></FONT></H2>
			<P>In some cases you might not want to see all the columns of the datasheet. Perhaps
			your display is too wide, you don't need to enter all information, or you only want
			to see relevant information to your task. Another option to help you navigate with
			many columns is to freeze columns. (See &quot;Freeze Display of a Table Field&quot;
			in the Database Essentials part of this book.)
			<H3><FONT COLOR="#000077"><B>Steps</B></FONT></H3>
			<DL>
				<DD><B>1. </B>Open a table, <I>query</I>, or <I>form</I> in <I>Datasheet View</I>.
				<P>
				<DD><B>2. </B>Right-click the column header and choose <U>H</U>ide Columns.
			</DL>
			<P>To return a hidden column to view, use the F<U>o</U>rmat, <U>U</U>nhide Columns
			command and check the box next to the column you want to see.


			<BLOCKQUOTE>
			<P>
<HR>
<FONT COLOR="#000077"><B>CAUTION:</B></FONT><B> </B>When hiding columns from view,
			be careful that you don't inadvertently neglect their data entry.