Apress.Expert.Oracle.Database.Architecture.9i.and.10g.Programming.Techniques.and.Solutions.Sep.2005

CHAPTER 12 ■ DATATYPES 519
We are ready to bind the inputs to this query. Any non-NULL names that were passed to us
will be “bound” to the query, so when we execute it, it finds the right row:
55 bind_variable( p_name1, p_bind1 );
56 bind_variable( p_name2, p_bind2 );
57 bind_variable( p_name3, p_bind3 );
58 bind_variable( p_name4, p_bind4 );
59
And now we can execute the query and fetch the row. Then using DBMS_SQL.COLUMN_
VALUE_LONG, we extract the necessary substring of the LONG and return it:
60 dbms_sql.define_column_long(g_cursor, 1);
61 if (dbms_sql.execute_and_fetch(g_cursor)>0)
62 then
63 dbms_sql.column_value_long
64 (g_cursor, 1, p_for, p_from-1,
65 l_buffer, l_buffer_len );
66 end if;
67 return l_buffer;
68 end substr_of;
69
70 end;
71 /
Package body created.
That’s it—you should be able to use that package against any legacy LONG column in
your database, allowing you to perform many WHERE clause operations that were not possible
before. For example, you can now find all partitions in your schema such that the HIGH_VALUE
has the year 2003 in it:
ops$tkyte@ORA10G> select *
2 from (
3 select table_owner, table_name, partition_name,
4 long_help.substr_of
5 ( 'select high_value
6 from all_tab_partitions
7 where table_owner = :o
8 and table_name = :n
9 and partition_name = :p',
10 1, 4000,
11 'o', table_owner,
12 'n', table_name,
13 'p', partition_name ) high_value
14 from all_tab_partitions
15 where table_name = 'T'
16 and table_owner = user
17 )
18 where high_value like '%2003%'