MACROMEDIA COLFUSION MX 7 - CONFIGURING AND ADMINISTERING COLDFUSION MX Manual page 18

The following table compares the client variable storage options:
Storage type
Data source
Browser cookies
System registry
Migrating client variable data
To migrate your client variable data to another data source, you should know the structure of the
database tables that store this information. Client variables stored externally use two simple
database tables, like those shown in the following tables:
CDATA Table
Column
cfid
app
data
CGLOBAL Table
Column
cfid
data
lvisit
Creating client variable tables
Use the following sample ColdFusion page as a model for creating client variable database tables
in your own database. However, keep in mind that not all databases support the same column
data type names. For the proper data type, see your database documentation.
Tip: The ColdFusion MX Administrator can create client variable tables for data sources that use one
of the bundled JDBC drivers. For more information, see the online help.
18 Chapter 2: Using the ColdFusion MX Administrator
Advantages
• Can use existing data source
• Portable: not tied to the host
system or operating system
• Simple implementation
• Good performance
• Can be set to expire automatically
• Client-side control
• Simple implementation
• Good performance
• Registry can be exported easily to
other systems
• Server-side control
Data type
CHAR(64), TEXT, VARCHAR, or equivalent
CHAR(64), TEXT, VARCHAR, or equivalent
MEMO, LONGTEXT, LONG VARCHAR, or equivalent
Data type
CHAR(64), TEXT, VARCHAR, or equivalent
MEMO, LONGTEXT, LONG VARCHAR, or equivalent
TIMESTAMP, DATETIME, DATE, or equivalent
Disadvantages
• Requires database transaction to
read/write variables
• More complex to implement
• Users can configure browsers to
disallow cookies
• Cookie data is limited to 4 KB
• Netscape Navigator allows only 20
cookies from one host; ColdFusion MX
uses three cookies to store read-only
data, leaving only 17 cookies available
• Possible restriction of the registry's
maximum size limit in Windows in the
Control Panel
• Integrated with the host system: not
practical for clustered servers
• Not available for UNIX