Firebird 2.5 creates databases with an ODS (On-Disk Structure) version of 11.2

Tracker reference CORE-1761.

Statements now return an SQL-2003 standard 5-alphanumeric SQLSTATE completion code. Further information to come.

Tracker reference CORE-1741.

The new option DSQL_unprepare (numeric value 4) for the API routine isc_dsql_free_statement() allows the DSQL statement handle to survive the “unpreparing” of the statement.

Previously, the isc_dsql_free_statement() function supported only DSQL_close (for closing a named cursor) and DSQL_drop (which frees the statement handle).

The API addition is:

#define DSQL_close 1
#define DSQL_drop 2
#define DSQL_unprepare 4
        

New fb_cancel_operation() API call, allowing cancellation of the current activity being performed by some kind of blocking API call in the given connection.

More information to come.

New fb_shutdown() API call. When used for the embedded engine, it terminates all the current activity, rolls back active transactions, disconnects active attachments and shuts down the engine gracefully.

More information to come.

This multi-threaded mode for Classic has been dubbed “Superclassic” for its capability to handle multiple worker threads—dedicated or pooled—inside a single server process. It shares all the usual Classic features, with a few differences:

fb_inet_server -a -m
            

The Classic server now detects immediately when a Classic process has been broken by a client disconnection. Its response is to terminate any pending activity, roll back the active transaction and close the network connection.

Tracker reference CORE-818.

Important optimizations include:

The root determination mechanism for the Windows embedded engine has been changed to avoid common problems that occur when an installation of the application structure encounters “DLL Hell”. Previously, the implicit root directory was the directory containing the user application's main executable file. Now it is the directory where the renamed fbembed.dll library is located.

Tracker reference CORE-1814.

Tracker reference CORE-1937.

When a string UDF is written to return a pointer not allocated by the same runtime as the Firebird server is accessing, the presence of the FREE_IT keyword in its declaration corrupts memory and crashes the server. As a safeguard against such dysfunctional UDFs, the engine now

Tracker reference CORE-696.

In v.2.5, Firebird finally has syntax to enable user accounts on the server to be managed by submitting SQL statements when logged in to a regular database.

Syntax Patterns

A user with SYSDBA privileges can add a new user:

CREATE USER <username> {PASSWORD 'password'}
  [FIRSTNAME 'firstname']
  [MIDDLENAME 'middlename']
  [LASTNAME 'lastname'];
      

A user with SYSDBA privileges can change one or more of the password and proper name attributes of an existing user. Non-privileged users can use this statement to alter only their own attributes.

ALTER USER <username>
  [PASSWORD 'password']
  [FIRSTNAME 'firstname']
  [MIDDLENAME 'middlename']
  [LASTNAME 'lastname'];
      

A user with SYSDBA privileges can delete a user:

DROP USER <username>;
      

Restrictions

CREATE and DROP statements are available only for the SYSDBA or a user that has been granted the RDB$ADMIN role in the security database. An ordinary user can ALTER his own password and elements of his proper name. An attempt to modify another user will fail.

Examples

CREATE USER alex PASSWORD 'test';

ALTER USER alex FIRSTNAME 'Alex' LASTNAME 'Peshkov';

ALTER USER alex PASSWORD 'IdQfA';

DROP USER alex;
      

Previously, in order to alter a view definition, it was necessary to save the view definition off-line somewhere and drop the view, before recreating it with its changes. This made things very cumbersome, especially if there were dependencies. V.2.5 introduces syntaxes for ALTER VIEW and CREATE OR ALTER VIEW.

Tracker references are CORE-770 and CORE-1640.

Syntax Pattern

create [ or alter ] | alter } view <view_name>
  [ ( <field list> ) ]
as <select statement>
      

Example

create table users (
    id integer,
    name varchar(20),
    passwd varchar(20)
);

create view v_users as
    select name from users;

alter view v_users (id, name) as
    select id, name from users;
      

Tracker reference CORE-886.

A selectable stored procedure can now be specified in the FROM clause of a view definition.

More information to come.

Tracker reference CORE-1454.

A column defined as COMPUTED BY <expression> can now be altered using the ALTER TABLE...ALTER COLUMN syntax. This feature can be used only to change the <expression> element of the column definition to a different expression. It cannot convert a computed column to non-computed or vice versa.

Syntax Pattern

alter table <table-name>
  alter <computed-column-name>
  [type <data-type>]
  COMPUTED BY (<expression>);
      

Examples

create table test (
  n integer,
  dn computed by (n * 2)
);
commit;
alter table test
  alter dn computed by (n + n);
      

A GRANTED BY or GRANTED AS clause can now be optionally included in GRANT and REVOKE statements, enabling the grantor to be a user other than the CURRENT_USER (the default).

Syntax Pattern

grant <right> to <object>
  [ { granted by | as } [ user ] <username> ]
--
revoke <right> from <object>
  [ { granted by | as } [ user ] <username> ]
      

Example

Logged in as SYSDBA:

create role r1; -- SYSDBA owns the role
  /* next, SYSDBA grants the role to user1
     with the power to grant it to others */
grant r1 to user1 with admin option;
  /* SYSDBA uses GRANTED BY to exercise
     user1's ADMIN OPTION */
grant r1 to public granted by user1;
      

In isql, we look at the effects:

Tracker reference CORE-1660.

The new ALTER ROLE statement has a specialised function to control the assignment of SYSDBA permissions to Windows administrators during trusted authentication. It has no other purpose currently.

For usage details, see the topic in the Administrative Features chapter, entitled Automatically Mapping RDB$ADMIN to a Windows User.

Tracker references CORE-1737 and CORE-1803.

An ODS 11.2 or higher database can now have a default COLLATION attribute associated with the default character set, enabling all text column, domain and variable definitions to be created with the same collation order unless a COLLATE clause for a different collation is specified.

The COLLATION clause is optional. If it is omitted, the default collation order for the character set is used.

Syntax Pattern

create database <file name>
    [ page_size <page size> ]
    [ length = <length> ]
    [ user <user name> ]
    [ password <user password> ]
    [ set names <charset name> ]
    [ default character set <charset name>
      [ collation <collation name> ] ]
    [ difference file <file name> ]
      

Example

create database 'test.fdb'
    default character set win1252
    collation win_ptbr;
      

Tracker reference CORE-1803.

New syntax introduced in this version, enabling the default collation for a character set to be set for a database.

The default collation is used when table columns are created with a given character set (explicitly, through a CHARACTER SET clause in the column or domain definition, or implicitly, through the default character set attribute of the database) and no COLLATION clause is specified.

Syntax Pattern

ALTER CHARACTER SET <charset_name>
    SET DEFAULT COLLATION <collation_name>
      

Example

create database 'people.fdb'
  default character set win1252;

alter character set win1252
  set default collation win_ptbr;

create table person (
  id integer,
  name varchar(50)  /* will use the database default
                       character set and the win1252
                       default collation */
);

insert into person
  values (1, 'adriano');
insert into person
  values (2, 'ADRIANO');

/* will retrieve both records
   because win_ptbr is case insensitive */
select * from person where name like 'A%';
      

Tracker reference CORE-769.

A new SIMILAR TO predicate is introduced to support regular expressions. The predicate's function is to verify whether a given SQL-standard regular expression matches a string argument. It is valid in any context that accepts Boolean expressions, such as WHERE clauses, CHECK constraints and PSQL IF() tests.

Syntax Patterns

<similar predicate> ::=
	<value> [ NOT ] SIMILAR TO <similar pattern> [ ESCAPE <escape character> ]

<similar pattern> ::= <character value expression: regular expression>

<regular expression> ::=
      <regular term>
    | <regular expression> <vertical bar> <regular term>

<regular term> ::=
      <regular factor>
    | <regular term> <regular factor>

<regular factor> ::=
      <regular primary>
    | <regular primary> <asterisk>
    | <regular primary> <plus sign>
    | <regular primary> <question mark>
    | <regular primary> <repeat factor>

<repeat factor> ::=
    <left brace> <low value> [ <upper limit> ] <right brace>

<upper limit> ::= <comma> [ <high value> ]

<low value> ::= <unsigned integer>

<high value> ::= <unsigned integer>

<regular primary> ::=
      <character specifier>
    | <percent>
    | <regular character set>
    | <left paren> <regular expression> <right paren>

<character specifier> ::=
      <non-escaped character>
    | <escaped character>

<regular character set> ::=
      <underscore>
    | <left bracket> <character enumeration>... <right bracket>
    | <left bracket> <circumflex> <character enumeration>... <right bracket>
    | <left bracket> <character enumeration include>... <circumflex> <character enumeration exclude>... 
        <right bracket>

<character enumeration include> ::= <character enumeration>

<character enumeration exclude> ::= <character enumeration>

<character enumeration> ::=
      <character specifier>
    | <character specifier> <minus sign> <character specifier>
    | <left bracket> <colon> <character class identifier> <colon> <right bracket>

<character specifier> ::=
      <non-escaped character>
    | <escaped character>

<character class identifier> ::=
      ALPHA
    | UPPER
    | LOWER
    | DIGIT
    | SPACE
    | WHITESPACE
    | ALNUM
      

Usage Guide

Return true for a string that matches <regular expression> or <regular term>: <regular expression> <vertical bar> <regular term>

    'ab' SIMILAR TO 'ab|cd|efg'   -- true
    'efg' SIMILAR TO 'ab|cd|efg'  -- true
    'a' SIMILAR TO 'ab|cd|efg'    -- false
       

Match zero or more occurrences of <regular primary>: <regular primary> <asterisk>

    '' SIMILAR TO 'a*'     -- true
    'a' SIMILAR TO 'a*'    -- true
    'aaa' SIMILAR TO 'a*'  -- true
       

Match one or more occurrences of <regular primary>: <regular primary> <plus sign>

    '' SIMILAR TO 'a+'     -- false
    'a' SIMILAR TO 'a+'    -- true
    'aaa' SIMILAR TO 'a+'  -- true
       

Match zero or one occurrence of <regular primary>: <regular primary> <question mark>

    '' SIMILAR TO 'a?'     -- true
    'a' SIMILAR TO 'a?'    -- true
    'aaa' SIMILAR TO 'a?'  -- false
       

Match exact <low value> occurrences of <regular primary>: <regular primary> <left brace> <low value> <right brace>

    '' SIMILAR TO 'a{2}'     -- false
    'a' SIMILAR TO 'a{2}'    -- false
    'aa' SIMILAR TO 'a{2}'   -- true
    'aaa' SIMILAR TO 'a{2}'  -- false
       

Match <low value> or more occurrences of <regular primary>: <regular primary> <left brace> <low value> <comma> <right brace>:

    '' SIMILAR TO 'a{2,}'     -- false
    'a' SIMILAR TO 'a{2,}'    -- false
    'aa' SIMILAR TO 'a{2,}'   -- true
    'aaa' SIMILAR TO 'a{2,}'  -- true
       

Match <low value> to <high value> occurrences of <regular primary> <regular primary> <left brace> <low value> <comma> <high value> <right brace>:

    '' SIMILAR TO 'a{2,4}'       -- false
    'a' SIMILAR TO 'a{2,4}'      -- false
    'aa' SIMILAR TO 'a{2,4}'     -- true
    'aaa' SIMILAR TO 'a{2,4}'    -- true
    'aaaa' SIMILAR TO 'a{2,4}'   -- true
    'aaaaa' SIMILAR TO 'a{2,4}'  -- false
       

Match any (non-empty) character: <underscore>

    '' SIMILAR TO '_'    -- false
    'a' SIMILAR TO '_'   -- true
    '1' SIMILAR TO '_'   -- true
    'a1' SIMILAR TO '_'  -- false
       

Match a string of any length (including empty strings): <percent>

    '' SIMILAR TO '%'         -- true
    'az' SIMILAR TO 'a%z'     -- true
    'a123z' SIMILAR TO 'a%z'  -- true
    'azx' SIMILAR TO 'a%z'    -- false
       

Group a complete <regular expression> to use as one single <regular primary> as a sub-expression: <left paren> <regular expression> <right paren>

    'ab' SIMILAR TO '(ab){2}'    -- false
    'aabb' SIMILAR TO '(ab){2}'  -- false
    'abab' SIMILAR TO '(ab){2}'  -- true
       

Match a character identical to one of <character enumeration>: <left bracket> <character enumeration>... <right bracket>

    'b' SIMILAR TO '[abc]'    -- true
    'd' SIMILAR TO '[abc]'    -- false
    '9' SIMILAR TO '[0-9]'    -- true
    '9' SIMILAR TO '[0-8]'    -- false
       

Match a character not identical to one of <character enumeration>: <left bracket> <circumflex> <character enumeration>... <right bracket>

    'b' SIMILAR TO '[^abc]'    -- false
    'd' SIMILAR TO '[^abc]'    -- true
       

Match a character identical to one of <character enumeration include> but not identical to one of <character enumeration exclude>: <left bracket> <character enumeration include>... <circumflex> <character enumeration exclude>...

    '3' SIMILAR TO '[[:DIGIT:]^3]'    -- false
    '4' SIMILAR TO '[[:DIGIT:]^3]'    -- true
       

Match a character identical to one character included in <character class identifier>. Refer to the table of Character Class Identifiers, above. May be used with <circumflex> to invert the logic (see above): <left bracket> <colon> <character class identifier> <colon> <right bracket>

    '4' SIMILAR TO '[[:DIGIT:]]'  -- true
    'a' SIMILAR TO '[[:DIGIT:]]'  -- false
    '4' SIMILAR TO '[^[:DIGIT:]]' -- false
    'a' SIMILAR TO '[^[:DIGIT:]]' -- true
       

Examples

create table department (
  number numeric(3) not null,
  name varchar(25) not null,
  phone varchar(14) 
  check (phone similar to '\([0-9]{3}\) [0-9]{3}\-[0-9]{4}' escape '\')
);

insert into department 
  values ('000', 'Corporate Headquarters', '(408) 555-1234');
insert into department 
  values ('100', 'Sales and Marketing', '(415) 555-1234');
insert into department 
  values ('140', 'Field Office: Canada', '(416) 677-1000');

insert into department
  values ('600', 'Engineering', '(408) 555-123'); -- check constraint violation

select * from department
  where phone not similar to '\([0-9]{3}\) 555\-%' escape '\';
      

Tracker reference CORE-1760.

Support for hexadecimal numeric and binary string literals has been introduced.

Syntax Patterns

<numeric hex literal> ::=
    { 0x | 0X } <hexit> [ <hexit>... ]

<binary string literal> ::=
    { x | X } <quote> [ { <hexit> <hexit> }... ] <quote>

<digit> ::=
    0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9

<hexit> ::=
    <digit> | A | B | C | D | E | F | a | b | c | d | e | f
      

Examples

select 0x10, cast('0x0F0000000' as bigint)
  from rdb$database;
select x'deadbeef'
  from rdb$database;
      

Tracker references CORE-1656 and CORE-1682.

Two new built-in functions, UUID_TO_CHAR and CHAR_TO_UUID, enable conversion between a UUID in the form of a CHAR(16) OCTETS string and the RFC4122-compliant form.

CHAR_TO_UUID( <string> )
        

select char_to_uuid('93519227-8D50-4E47-81AA-8F6678C096A1')
  from rdb$database;
        

UUID_TO_CHAR( <string> )
        

select uuid_to_char(gen_uuid())
  from rdb$database;
        

Tracker reference CORE-1453

A string expression is now allowed as the delimiter argument of the LIST() function.

Example

SELECT
  DISCUSSION_ID,
  LIST(COMMMENT, ASCII_CHAR(13))
FROM COMMENTS
  GROUP BY DISCUSSION_ID;
      

If there is no ON EXTERNAL DATA SOURCE clause present, EXECUTE STATEMENT is normally executed within the CURRENT_CONNECTION context. This will be the case if the AS USER clause is omitted, or it is present with its <user_name> argument equal to CURRENT_USER.

However, if <user_name> is not equal to CURRENT_USER, then the statement is executed in a separate connection, established without Y-Valve and remote layers, inside the same engine instance.

Tracker reference CORE-1853.

EXECUTE STATEMENT now supports queries against external databases by inclusion of the ON EXTERNAL DATA SOURCE clause with its <connection_string> argument.

   [<host_name><protocol_delimiter>]database_path