Display query results
Once you create a query in the application file, you can reference the query results in other cfm files. Query results can be used to dynamically generate HTML webpages.
When you learn how to use CFML labels, remember that you can also use HTML labels and text in programs. ColdFusion simply transmits tags and text directly to the client browser where you use HTML tags and text. The most flexible way to output query results is to use the cfoutput tag. The cfoutput tag can be used to output a specific query or multiple queries. A cfoutput tag can contain:
· Plain text
· HTML Tag
· Reference query Fields
· Reference dynamic parameters, such as form fields
· Functions
The basic output Code has the following syntax:
<Cfoutput query = "queryname" maxrows = n>
Literal text, HTML tags, and
Dynamic Field references (e.g., # fullname #)
</Cfoutput>
Database field name in cfoutput
Some databases, such as Microsoft Access, can contain spaces in field names, such as "region name .". ColdFusion does not support reference such fields in cfoutput. To be compatible with ColdFusion, avoid using spaces in table names and field names, which gives applications maximum compatibility with different database systems. You can use underlines as separators, such as "region_name ".
The field name must start with a letter and can only contain letters and numbers. You can use the SQL keyword as to create an alias for the field name. For example, the statement:
Select 401 K as FK from employee_withholding
The cfquery can be correctly processed.
Example: cfoutput
In the following example, we use the cfoutput tag to display the query results of the employeelist query. Select the name, name, and phone number of each employee. Specifying a query name in a variable name is a good programming habit.
The complete code of the program is given below:
<! --- Query to select MERs --->
<Cfquery name = "employeelist" datasource = "companydb">
Select *
From employees
</Cfquery>
<HTML>
<Head>
<Title> employee list </title>
</Head>
<Body>
<H2> employee list </H2>
<! --- Output section --->
<Cfoutput query = "employeelist">
<HR>
# Employeelist. firstname # employeelist. lastname #
(PHONE: # employeelist. phonenumber #) <br>
</Cfoutput>
</Body>
</Html>
You can directly apply for this webpage through URL, for example:
Http: // myserver/cfdocs/employeelist. cfm
Or use a hyperlink to reference:
<A href = "myserver/cfdocs/employeelist. cfm"> employee list </a>
The HTML code of the output result in this example is similar:
<HR>
Deborah Jones (phone: 612-227-1019) <br>
<HR>
John smith (phone: 507-452-7224) <br>
<HR>
Frank Wilson (phone: 612-831-9555) <br>
Nested cfoutput and group
You can nest cfoutput to display query results in groups. The implementation of grouping is to specify the group attribute of the cfoutput tag, and then embed another cfoutput into the previous cfoutput. The content above and below in the inner cfoutput is used to display a title and footer information for each group.
Example: Group
The following code uses the group attribute of cfoutput to display the query result group according to the value of "courselevel. The order by keyword sorts the query results based on the value of the courselevel field. Cfoutput nesting does not limit the number of layers. If you want to use multi-level grouping, you need to set multi-level sorting in SQL queries (for example, "order by region, state ").
<Cfquery name = "courses" datasource = "coursedb">
Select *
From courselist
Where department_id =? Form. Department #
Order by courselevel
</Cfquery>
<Cfoutput query = "courses" group = "courselevel">
<H4> # courselevel # </H4>
<Ul>
<Cfoutput>
<Li> # coursenumber #-# coursename #
</Cfoutput>
</Ul>
</Cfoutput>
In this example, the result displayed in the browser is:
Basic
100-physiology
Intermediate
510-neurobiology
500-Plant Biology
Advanced
820-neurobiology
800-Microbiology
Cfquery attributes
Each cfquery has three attributes that provide the number of records.
| Number of records |
|
| Number of records |
Description |
| Recordcount |
Query the total number of returned records. |
| Currentrow |
The current record being processed by cfoutput. |
| Columnlist |
Returns the list of query fields separated by commas. |
Example: query a field
In this example, the number of records in the customerlist query and the list of query fields are returned:
<Cfoutput>
The search returned information
On # customerlist. recordcount # customers. <br>
Columns queried were # customerlist. columnlist #.
</Cfoutput>
To display the sequence number of each record, you can use the following syntax:
<Cfoutput query = "customerlist">
# Currentrow #-# firstname # lastname # <br>
</Cfoutput>
Returns part of a record set.
For a large record set, you may want to display only a portion of the record set. This can be done using the startrow and maxrows attributes of the cfoutput tag. Startrow specifies the first record in the record set to be returned. Maxrows specifies the total number of records to be returned.
Example: A part of a record set
In this example, 10th to 20 records are queried in the result record set of employeelist:
<Cfoutput query = "employeelist"
Startrow = "10" maxrows = "20">
# Firstname # lastname # Phone # <br>
</Cfoutput>
Use parameters in cfoutput
Cfoutput is not only used to display the queried data. You can also use cfoutput to display form variables, URL variables, Cookie, client variables, server variables, session variables, Application variables, and CGI environment variables. Note the correct prefix When referencing these variables so that ColdFusion can distinguish these variables from the field names of the query results. Like the query field, the variable must be added to the well number. The parameter values of each record in the query results are displayed once. Note: To display the well number itself, apply two consecutive well numbers to indicate one well number.
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