android - transitive-closure-table example -

i know transitive-closure concept used storing tree structures data. concept used retrieve hierarchical data in efficient , minimum complex query.

in sqlite query browser, have tried these queries:

create table category (     id integer not null primary key,     name varchar(255),     parent_id integer,     foreign key (parent_id) references category (id) );   create virtual table category_closure using transitive_closure (     tablename="category",     idcolumn="id",     parentcolumn="parent_id" ); 

i able create table using query no. 1 query no. 2 not working.

can provide specific example in android using sqlite?

as shown in blog post querying tree structures in sqlite using python , transitive closure extension, transitive closure extension must compiled manually. not possible when using default android database api.

you use triggers maintain explicit closure table.