Language Reference

Language Reference by Helmut Emmelmann, PhD and Keith Oustalet

heitml Tags to access the database

Accessing the database is done by the <dbquery> tag. It has the following syntax:

<dbquery queryname> SQL-Querystatement <dbrow> text for every row <dbtop> top of table <dbfoot> foot of table <dbempty> in case of empty result </dbquery>

The SQL-Querystatement must be a valid SQL-SELECT statement. The SQL-Querystatement is processed in HTML mode . All heitml tags can be used to generate the desired SQL-Query.

The SQL statement is executed and the row section is processed repeatedly for every row selected. The row section is processed in HTML mode. It may contain the ? tag to include the content of a database field within the page. However, the row part may contain any other HTML or heitml tags, including nested queries or update statements.

An arbitrary queryname can be choosen distinct from the names of local variables. The fields of the selected rows are accessed by writing queryname.fieldname (e.g. if the query was named q, then <? q.firstname> prints the firstname field in the database). In fact queryname denotes a heitml tuple that contains the current row. The tuple can be read as any other tuple but it can not be written.

The empty section is processed (in HTML mode) if the result of the select statement is empty. Otherwise top and foot sections are processed once, in the beginning and at the end of the table respectively. The advantage of the top and foot section over writing the table head and table foot before and after the query tag is that in case of an empty result table only the text in the empty section is displayed.

Modifying the Database

<dbupdate> SQL-Statement </dbupdate>

The update tag can contain SQL update, delete or insert statements. With appropiate database systems also many other SQL statements are allowed, including create table etc.

The SQL statement is passed unaltered to the database system and is executed immediately.

Format: <dbdatabase > heitml </dbdatabase>

Select a database. This is neccessay only if you want to change the database during processing. (See also configuartion files.)

Accessing Anonymous Relations

<dbquery queryname> SQL-Querystatement 
   <dbhead>         headline for a column  
   <dbbody>         sperator between head & body 
   <dbrow>          text for every row
   <dbcolumn>       text for column 
   <dbrowend>       end of text for every row
</dbquery>