- Documentation
- Reference manual
- Packages
- Constraint Query Language A high level interface to SQL databases
- library(cql/cql): CQL - Constraint Query Language
- Examples
- Simple INSERT
- Simple INSERT with retrieval of identity of the inserted
- Simple DELETE
- Simple SELECT
- Simple UPDATE
- WHERE with arithmetic comparison
- Simple INNER JOIN
- Arithmetic UPDATE with an INNER JOIN and a WHERE restriction
- Confirm row does not exist
- Aggregation - Count
- Aggregation - Sum
- Aggregation - Average
- Maximum Value
- Minimum Value
- Aggregation requiring GROUP BY
- INNER JOIN with an aggregation sub-query where the sub-query is constrained by a shared variable from the main query
- INNER JOIN in an aggregation sub-query
- Negation
- EXISTS
- Left Outer Join
- List-based Restrictions
- Compile time in-list constraint
- Disjunction resulting in OR in WHERE clause
- Disjunction resulting in different joins (implemented as a SQL UNION)
- Disjunction resulting in different SELECT attributes (implemented as separate ODBC queries)
- ORDER BY
- DISTINCT
- SELECT with NOT NULL restriction
- First N
- Self JOIN
- Removing null comparisions
- Three table JOIN
- Three table JOIN with NOLOCK locking hint
- SELECT with LIKE
- Writing exceptions directly to the database
- TOP N is Parametric
- Using compile_time_goal/1
- ON
- Expressions In Where Restrictions
- Explicitly avoid the "No WHERE restriction" message
- HAVING
- INSERT and UPDATE value in-line formatting
- Negations in WHERE Clauses
- Predicate-generated Attribute Values
- INSERT from SELECT
- Examples
- library(cql/cql): CQL - Constraint Query Language
- Constraint Query Language A high level interface to SQL databases
1.7.35 Writing exceptions directly to the database
You can write an exception term directly to a varchar-type column in
the database. Note that it will be rendered as text using ~p,
and truncated if necessary - so you certainly can't read it out again
and expect to get an exception! Example code:
catch(process_message(Message),
Exception,
{[],
update(some_table, [status-'ERROR',
status_comment-Exception]),
@ :: [some_table_primary_key-PrimaryKey]}).
FIXME: This code is specific to my usage of CQL