* Oleg Bartunov <oleg@sai.msu.su>, Moscow, Moscow University, Russia

* Teodor Sigaev <teodor@sigaev.ru>, Moscow, Delta-Soft Ltd.,Russia

License

Stable version, included into PostgreSQL distribution, released under BSD license. Development version, available from this site, released under the GNU General Public License, version 2 (June 1991).

LEGAL NOTICES: This module is released under BSD license (as PostgreSQL

itself)

Operations

t

(1 row)

* hstore ~ hstore - contained operation, check if left operand is contained in right

* hstore ~ hstore - contained operation, check if left operand is contained

in right

Functions

1

2

* delete (hstore,text) - delete (key,value) from hstore if key matches argument.

* delete (hstore,text) - delete (key,value) from hstore if key matches

argument.

regression=# select delete('a=>1,b=>2','b');

delete

a | 1

b | 2

* isexists (hstore,text) - returns 'true if key is exists in hstore and false otherwise.

* isexists (hstore,text) - returns 'true if key is exists in hstore and

false otherwise.

regression=# select isexists('a=>1','a');

isexists

----------

t

* isdefined (hstore,text) - returns true if key is exists in hstore and its value is not NULL.

* isdefined (hstore,text) - returns true if key is exists in hstore and

its value is not NULL.

regression=# select isdefined('a=>NULL','a');

isdefined

* Statistics

hstore type, because of its intrinsic liberality, could contain a lot of different keys. Checking for valid keys is the task of application. Examples below demonstrate several techniques how to check keys statistics.

hstore type, because of its intrinsic liberality, could contain a lot of

different keys. Checking for valid keys is the task of application.

Examples below demonstrate several techniques how to check keys statistics.

o simple example

public | 194

title | 190

org | 189

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