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WebChess: no flash, no registration. Nice and simple. Editor's choice. :) Read more...

Skype Commands

Создателя конференц-чата в Скайпе можно узнать при помощи команды
/get creator

Создатель конференц-чата может отсоединить от чата любого из участвующих командой
/kick [skypename]

Остальные команды можно узнать, введя
/help

Список команд:
/me [text]
/topic [text]
/add [skypename]
/history
/find [text]
/fa or /
/alertson [text]
/alertsoff
/call [skypename] ..
/leave
/goadmin
/get creator
/get role
/whois [skypename]
/setrole [skypename] MASTERHELPERUSERLISTENER
/kick [skypename]
/kickban [skypename]
/get guidelines
/set guidelines [text]
/get options
/set options [[+-]flag] ..
/setpassword [password] [password hint]
/clearpassword
/get password_hint
/set password_hint [text]
/set password [text]
/get banlist
/get allowlist
/set banlist [[+-]mask] ..
/set allowlist [[+-]mask] ..
/help


[#]

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O rus! - О деревня!

и другие римские изречения Read more...

JavaDB: Check constraints

create table FREQUENCIES (
 NAME varchar(20) check (NAME in ('daily', 'weekly', 'monthly', 'yearly'))
);
insert into FREQUENCIES (NAME) values ('daily'), ('monthly');
select * from FREQUENCIES;

However something like

insert into FREQUENCIES (NAME) values ('hourly');

will lead to an error:

Error code -1, SQL state 23513: The check constraint 'SQL090305033046840' was violated while performing an INSERT or UPDATE on table 'ADMIN.FREQUENCIES'.
Line 1, column 1

See also "JavaDB 10.1.3: ALTER TABLE statement". Read more...

JavaDB: Default values for TIMESTAMP fields

create table LOG (
ID int primary key generated always as identity (start with 2147483647, increment by -1),
 -- the largest INTEGER: see 'Numeric Limitations' at http://developers.sun.com/docs/javadb/10.2.2/ref/rrefnumericlimits.html
T timestamp with default current_timestamp,
 -- see 'CREATE TABLE statement' at http://developers.sun.com/docs/javadb/10.2.2/ref/rrefsqlj24513.html
 -- and 'CURRENT TIMESTAMP' at http://developers.sun.com/docs/javadb/10.2.2/ref/rrefsqlj15866.html#rrefsqlj15866
MSG varchar(32672)
 -- maximal length of VARCHAR: see 'String Limitations' at http://developers.sun.com/docs/javadb/10.2.2/ref/rrefstringlimits.html
);

insert into LOG (MSG) values ('Rolling back the current changes...');
insert into LOG (MSG) values ('Starting a new transaction...');
insert into LOG (MSG) values ('Fetching new data...');
insert into LOG (MSG) values ('Done!');

select * from LOG order by T;
select ID, cast (T as CHAR(23)) as TIMESTAMP, MSG from LOG;

2147483647 2009-03-02 16:50:03.614 Rolling back the current changes...
2147483646 2009-03-02 16:50:03.692 Starting a new transaction...
2147483645 2009-03-02 16:50:03.708 Fetching new data...
2147483644 2009-03-02 16:50:03.723 Done!

See also:

• JavaDB 10.1.3: Data types
• Limitations of JavaDB

Read more...

JavaDB: Auto-generation of primary keys

create table PKTEST (
    ID int primary key generated always as identity,
    TXT varchar(12345)
);
insert into PKTEST (TXT) values ('aaa'), ('bbb'), ('ccc');
select * from PKTEST;
drop table PKTEST;

У опции "generated always as identity" есть два параметра - "start with" и "increment by".

create table PKTEST (
    ID int primary key generated always as identity (start with 100000, increment by 10),
    TXT varchar(12345)
);

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