--- /dev/null
+drop table computer_terms;
+ERROR: Relation 'computer_terms' does not exist
+create table computer_terms(term text, category text, comments char(16));
+create index computer_terms_index1 on computer_terms using btree(term);
+create index computer_terms_index2 on computer_terms using btree(category);
+insert into computer_terms values('computer display', 'X-A01-Y', 'a comment 1');
+insert into computer_terms values('computer graphics', 'T-B01-Y', 'a comment 2');
+insert into computer_terms values('computer programmer', 'S-Z01-Y', 'a comment 3');
+vacuum computer_terms;
+select * from computer_terms;
+ term | category | comments
+---------------------+----------+------------------
+ computer display | X-A01-Y | a comment 1
+ computer graphics | T-B01-Y | a comment 2
+ computer programmer | S-Z01-Y | a comment 3
+(3 rows)
+
+select * from computer_terms where category = 'X-A01-Y';
+ term | category | comments
+------------------+----------+------------------
+ computer display | X-A01-Y | a comment 1
+(1 row)
+
+select * from computer_terms where category ~* 'x-a01-y';
+ term | category | comments
+------------------+----------+------------------
+ computer display | X-A01-Y | a comment 1
+(1 row)
+
+select * from computer_terms where category like '_-A01-_';
+ term | category | comments
+------------------+----------+------------------
+ computer display | X-A01-Y | a comment 1
+(1 row)
+
+select * from computer_terms where category like '_-A%';
+ term | category | comments
+------------------+----------+------------------
+ computer display | X-A01-Y | a comment 1
+(1 row)
+
+select * from computer_terms where term ~ 'computer [dg]';
+ term | category | comments
+-------------------+----------+------------------
+ computer display | X-A01-Y | a comment 1
+ computer graphics | T-B01-Y | a comment 2
+(2 rows)
+
+select * from computer_terms where term ~* 'computer [DG]';
+ term | category | comments
+-------------------+----------+------------------
+ computer display | X-A01-Y | a comment 1
+ computer graphics | T-B01-Y | a comment 2
+(2 rows)
+
+select *,character_length(term) from computer_terms;
+ term | category | comments | length
+---------------------+----------+------------------+--------
+ computer display | X-A01-Y | a comment 1 | 16
+ computer graphics | T-B01-Y | a comment 2 | 17
+ computer programmer | S-Z01-Y | a comment 3 | 19
+(3 rows)
+
+select *,octet_length(term) from computer_terms;
+ term | category | comments | octet_length
+---------------------+----------+------------------+--------------
+ computer display | X-A01-Y | a comment 1 | 16
+ computer graphics | T-B01-Y | a comment 2 | 17
+ computer programmer | S-Z01-Y | a comment 3 | 19
+(3 rows)
+
+select *,position('s' in term) from computer_terms;
+ term | category | comments | strpos
+---------------------+----------+------------------+--------
+ computer display | X-A01-Y | a comment 1 | 12
+ computer graphics | T-B01-Y | a comment 2 | 17
+ computer programmer | S-Z01-Y | a comment 3 | 0
+(3 rows)
+
+select *,substring(term from 10 for 4) from computer_terms;
+ term | category | comments | substr
+---------------------+----------+------------------+--------
+ computer display | X-A01-Y | a comment 1 | disp
+ computer graphics | T-B01-Y | a comment 2 | grap
+ computer programmer | S-Z01-Y | a comment 3 | prog
+(3 rows)
+