Getting Data from your Database

Using the Results of TCL Commands

The normal way to access Reality data from DataBasic is to use the File I/O or Sequential File Access statements and functions. However, in many cases you may find it easier to use TCL and English commands to generate text for your web page. Use the PERFORM statement with a CAPTURING clause, and then copy the results to the appropriate buffer with RW_TRANS. That is:

PERFORM TclCommand CAPTURING Result
CALL RW_TRANS(Output, RWD_NORMAL)

where TclCommand evaluates to a string containing the required TCL or English command, Result is the name of a variable in which the results will be returned, and RWD_NORMAL specifies the normal output buffer.

You can, if necessary, process the results of the TCL command before copying it to the buffer.

HTML Tables

If you want to display your data in a table, you may find that using LIST-SPREAD or SORT-SPREAD in conjunction with RW_MAKE_TABLE or RWA_MAKE_TABLE produces the results you require. For example:

* Get the data to go in the table.
PERFORM "SORT-SPREAD GUESTS < '200' " : ...
    "ROOM NAME ADDRESS CITY STATE ZIP ID-SUPP" ...
    CAPTURING aData
* Get the headings from the second attribute.
DEL aData<1>
aHeadings = aData<1>
* SORT-SPREAD returns tab-separated data; convert it to a dynamic array.
aHeadings = CHANGE(aHeadings, TAB, @AM)
* The data is in the third attribute onwards.
DEL aData<1>
* SORT-SPREAD returns tab-separated data; convert it to a dynamic array.
aData = CHANGE(aData, TAB, @VM)
* Create the table.
CALL RWA_MAKE_TABLE(HTML, aHeadings, aData, "", aClass, RWD_IGNORE_EMPTY_ROWS)
* Output the HTML.
CALL RW_PUT(HTML)

Using HTML Templates

If you wish, you can create a template using a commercial HTML editor (such as Adobe DreamWeaver or Microsoft Expression Web) and then use RW_INSERT_CONV_ITEM or RWA_INSERT_CONV_ITEM to insert data from a dynamic array. The template can be a file on the host system, made available to Reality through a directory view.

The template must contain one or more tokens, enclosed in a specified delimiter character. For example, if the delimiter character is specified as "#", the text #value1# represents the token "value1".

When you call RW_INSERT_CONV_ITEM or RWA_INSERT_CONV_ITEM you must supply two dynamic arrays, one containing a list of tokens (without delimiter characters) and the other the data to be substituted for those tokens. Each attribute in the tokens array is replaced by the corresponding attribute in the data array.

For examples, see RW_INSERT_CONV_ITEM or RWA_INSERT_CONV_ITEM.

Using Item Locks with Persistent Connections

If a subroutine opens and then reads from a file, setting an item lock, upon completion of the subroutine the file will be closed and any locks released. When using a persistent connection, however, you would normally want to hold the item lock. To prevent the lock being released, open the file to a common variable.