Documentation Source Text

All string values at the SQL level in SQLite are dynamic strings.  
Requiring type strings to be static makes it difficult to 
create an application-defined SQL function that
can synthesize a pointer of an arbitrary type.  We do not want users
to create such SQL functions, since such functions would compromise the
security of the system.  Thus, the requirement to use static strings
helps to defend that the integrity of the pointer-passing interfaces against
ill-designed SQL functions.  The static string requirement is not
a perfect defense, since a sophisticated programmer can code around
it, and a novice program can simply take the memory leak.  But by
stating that the pointer type string must be static, we hope to encourage
developers who might otherwise use a dynamic string for the pointer type
to think more carefully about the problem and avoid introducing
security issues.

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Having SQLite take ownership of the type strings would impose a performance
cost on all applications, even applications that do not use the 
pointer-passing interfaces.  SQLite passes values around as instances
of the [sqlite3_value] object.  That object has a destructor, which because
of the fact that sqlite3_value objects are used for nearly everything, is