Firebird 2.1 Language Reference Update

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Chapter 9 Available in: DSQL, PSQL Added in: 1.5 Changed in: 2.1 Context variables CURRENT_CONNECTION Description: CURRENT_CONNECTION contains the unique identifier of the current connection. Type: INTEGER Examples: select current_connection from rdb$database execute procedure P_Login(current_connection) The value of CURRENT_CONNECTION is stored on the database header page and reset to 0 upon restore. Since version 2.1, it is incremented upon every new connection. (In previous versions, it was only incremented if the client read it during a session.) As a result, CURRENT_CONNECTION now indicates the number of connections since the creation – or most recent restoration – of the database. Available in: DSQL, PSQL Added in: 1.0 CURRENT_ROLE Description: CURRENT_ROLE is a context variable containing the role of the currently connected user. If there is no active role, CURRENT_ROLE is NONE. Type: VARCHAR(31) Example: if (current_role 'MANAGER') then exception only_managers_may_delete; 109
Context variables else delete from Customers where custno = :custno; CURRENT_ROLE always represents a valid role or NONE. If a user connects with a non-existing role, the engine silently resets it to NONE without returning an error. Available in: DSQL, PSQL, ESQL Changed in: 2.0 CURRENT_TIME Description: CURRENT_TIME returns the current server time. In versions prior to 2.0, the fractional part used to be always “.0000”, giving an effective precision of 0 decimals. From Firebird 2.0 onward you can specify a precision when polling this variable. The default is still 0 decimals, i.e. seconds precision. Type: TIME Syntax: Examples: Notes: CURRENT_TIME [(precision)] precision ::= 0 | 1 | 2 | 3 The optional precision argument is not supported in ESQL. select current_time from rdb$database -- returns e.g. 14:20:19.6170 select current_time(2) from rdb$database -- returns e.g. 14:20:23.1200 • Unlike CURRENT_TIME, the default precision of CURRENT_TIMESTAMP has changed to 3 decimals. As a result, CURRENT_TIMESTAMP is no longer the exact sum of CURRENT_DATE and CURRENT_TIME, unless you explicitly specify a precision. • Within a PSQL module (procedure, trigger or executable block), the value of CURRENT_TIME will remain constant every time it is read. If multiple modules call or trigger each other, the value will remain constant throughout the duration of the outermost module. If you need a progressing value in PSQL (e.g. to measure time intervals), use 'NOW'. Available in: DSQL, PSQL, ESQL CURRENT_TIMESTAMP 110
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Firebird 2.1 Language Reference Upd
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Table of Contents 1. Introduction .
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Firebird 2.1 Language Ref. Update F
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Firebird 2.1 Language Ref. Update A
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Firebird 2.1 Language Ref. Update s
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Chapter 1 Introduction Subject matt
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Chapter 2 Reserved words and keywor
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LOCK LOG LOG10 LPAD MATCHED MATCHIN
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Chapter 3 Available in: DSQL, PSQL
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Example: select name, age, case upp
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Data types and subtypes • Partial
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Added in: 1.0, 1.5, 1.5.1, 2.0, 2.1
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Chapter 5 DDL statements The statem
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With a special attribute (case-sens
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DIFFERENCE FILE parameter Added in:
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CREATE DOMAIN Available in: DSQL, E
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Example: DDL statements create exce
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Syntax: Example: ALTER EXTERNAL FUN
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DDL statements -- the following que
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DDL statements PROCEDURE A stored p
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DDL statements Description: Firebir
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DDL statements NOT NULL in variable
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CREATE GENERATOR Available in: DSQL
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Better alternative: DROP SEQUENCE D
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) DDL statements lastname varchar(2
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USING INDEX subclause Available in:
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ALTER COLUMN: SET DEFAULT Available
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UNIQUE constraints now allow NULLs
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Example: DDL statements create trig
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Multi-action triggers Added in: 1.5
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NOT NULL in variable declarations C
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DDL statements Restriction on recre
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DDL statements got a chance to put
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ORDER BY Available in: DSQL, PSQL A
Page 70 and 71: DML statements ROWS can also be use
Page 72 and 73: DML statements COLLATE in variable
Page 74 and 75: The same call in ESQL (with obligat
Page 76 and 77: DML statements Description: A SELEC
Page 78 and 79: DML statements Aggregate functions
Page 80 and 81: Syntax: Example: Notes: ::= DML
Page 82 and 83: DML statements select d.dept_no, d.
Page 84 and 85: DML statements FIRST and SKIP are b
Page 86 and 87: DML statements select strlen(lastna
Page 88 and 89: DML statements Description: A natur
Page 90 and 91: DML statements • Only non-negativ
Page 92 and 93: Example: DML statements plan (MyTab
Page 94 and 95: UNIONs in subqueries Changed in: 2.
Page 96 and 97: Restrictions DML statements • The
Page 98 and 99: DML statements Description: Limits
Page 100 and 101: Chapter 7 Available in: DSQL Added
Page 102 and 103: Transaction control statements If t
Page 104 and 105: Transaction control statements •
Page 106 and 107: Chapter 8 PSQL statements PSQL - Pr
Page 108 and 109: PSQL statements • If sql_datatype
Page 110 and 111: Warning PSQL statements If you chan
Page 112 and 113: PSQL statements exception ex_bad_ty
Page 114 and 115: PSQL statements as declare variable
Page 116 and 117: Examples: PSQL statements thoroughl
Page 118 and 119: leave; end end c = 0; PSQL statemen
Page 122 and 123: Changed in: 2.0 Context variables D
Page 124 and 125: Context variables its execution was
Page 126 and 127: Context variables Description: OLD
Page 128 and 129: Chapter 10 Changed in: 2.0 Operator
Page 130 and 131: UNION as subselect Changed in: 2.0
Page 132 and 133: Chapter 11 Aggregate functions Aggr
Page 134 and 135: Chapter 12 Available in: DSQL, PSQL
Page 136 and 137: • If the argument is NULL, NULL i
Page 138 and 139: Result type: INTEGER or BIGINT Synt
Page 140 and 141: Result type: INTEGER Syntax: BIT_LE
Page 142 and 143: Internal functions This gives you c
Page 144 and 145: Available in: DSQL, PSQL Added in:
Page 148 and 149: Example: The equivalent CASE constr
Page 150 and 151: WEEK Bug alert Internal functions M
Page 152 and 153: Added in: 2.1 Internal functions De
Page 154 and 155: Internal functions • If x is nega
Page 156 and 157: Examples: Internal functions lpad (
Page 158 and 159: Internal functions This will return
Page 160 and 161: Internal functions overlay ('Goodby
Page 164 and 165: Internal functions Description: Cre
Page 166 and 167: Internal functions reverse ('Was it
Page 168 and 169: Added in: 2.1 Internal functions De
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Syntax: SINH (number) Important Int
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Available in: DSQL, PSQL Added in:
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Notes: Internal functions • If th
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Description: Returns the arc cosine
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Declaration: External functions (UD
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Library: ib_udf Changed in: 1.0, 2.
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Better alternative: Internal functi
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External functions (UDFs) Descripti
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Syntax: cot (angle) Declaration: Ex
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Declaration: External functions (UD
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Library: ib_udf Added in: IB Change
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Changed in: 1.5, 1.5.2, 2.0 Better
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External functions (UDFs) DECLARE E
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See sright. Library: fbudf Added in
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Notes: External functions (UDFs) Fo
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Syntax: sign (number) Declaration:
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Library: fbudf Added in: 1.0 (Win),
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Notes: External functions (UDFs) th
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Better alternative: Internal functi
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Appendix A: Notes Character set NON
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Table A.1. How TPB settings affect
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Notes A note on CSTRING parameters
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Notes Maximum number of indices in
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Document History DDL statements ::
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Document History Internal functions
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Appendix C: License notice The cont
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Firebird 2.1 Language Reference Update

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