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Refining Your Queries with Field, Field List, and Query Properties
You can use field and query properties to refine and control the behavior and appearance of the columns in your query and of the query itself. Here's how:
NOTEIf you click a field within the query design grid that has its Show check box cleared, only the query properties will display when you bring up the Properties window for that field, not the field properties. If you mark the Show check box with the Properties window open, the field properties will then display.
Field Properties: Changing the Behavior of a Field
The properties of a field in your query include the Description, Format, Input Mask, and Caption of the column. The Description property documents the use of the field and controls what appears on the status bar when the user is in that column in the query result. The Format property is the same as the Format property in a table's field; it controls the display of the field in the query result. The Input Mask property, like its table counterpart, actually controls how the user enters and modifies data in the query result. The Caption property in the query does the same thing as a Caption property of a fieldit sets the caption for the column in Datasheet view and the default label for forms and reports.You might be wondering how the properties of the fields in a query interact with the same properties of a table. For example, how does the Caption property of a table's field interact with the Caption property of the same field in a query? All properties of a table's field are automatically inherited in your queries. Properties explicitly modified in the query override those same properties of a table's fields. Any objects based on the query inherit the properties of the query, not those of the original table.NOTEIn the case of the Input Mask property, it is important that the Input Mask of the query not be in conflict with the Input Mask of the table. You can use the Input Mask of the query to further restrict the Input Mask of the table, but not to override it. If the query's Input Mask conflicts with the table's Input Mask, the user will not be able to enter data into the table.
Field List Properties: Changing the Properties of the Field List
Field List properties specify attributes of each table participating in the query. The two Field List properties are Alias and Source. The Alias property is used most often when the same table is used more than once in the same query. This is done in self-joins, covered in Chapter 11. The Source property specifies a connection string or database name when you're dealing with external tables that aren't linked to the current database.
Query Properties: Changing the Behavior of the Overall Query
Microsoft offers many properties, shown in Figure 4.34, that allow you to affect the behavior of the overall query. Some of the properties are discussed here; the rest are covered as applicable throughout this book.
Figure 4.34. Query properties that affect the behavior of a given query.
The Description property documents what the query does. The Default View property was introduced with Access 2002. This property determines which view will display by default whenever the query is run. Datasheet is the default setting; PivotTable or PivotChart are the other two Default View settings that are available. Output All Fields shows all the fields in the query results, regardless of the contents of the Show check box in each field. Top Values lets you specify the top x number or x percent of values in the query result. The Unique Values and Unique Records properties are used to determine whether only unique values or unique records are displayed in the query's output. (These properties are also covered in detail in Chapter 11.)Chapter 28, "Advanced Security Techniques." Source Database, Source Connect String, ODBC Timeout, and Max Records all have to do with client/server issues and are covered in a separate book, Alison Balter's Mastering Access 2002 Enterprise Development . The Record Locks property concerns multiuser issues and is also covered in Alison Balter's Mastering Access 2002 Enterprise Development . The Recordset Type property determines whether updates can be made to the query output. By default, this is set to the Dynaset type, allowing updates to the underlying data. Filter displays a subset that you determine, rather than the full result of the query. Order By determines the sort order of the query. The Orientation property determines whether the visual layout of the fields is left-to-right or right-to-left. The Subdatasheet Name property allows you to specify the name of the table or query that will appear as a subdatasheet within the current query. After you set the Subdatasheet Name property, the Link Child Fields and Link Master Fields properties designate the fields from the child and parent tables or queries that are used to link the current query to its subdatasheet. Finally, the Subdatasheet Height property sets the maximum height for a subdatasheet, and the Subdatasheet Expanded property determines whether the subdatasheet automatically appears in an expanded state.
