Firebird 2.1 Language Reference Update

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DDL statements Restriction on recreating used triggers Changed in: 2.0, 2.0.1 Description: In Firebird 2.0 only, a restriction is in place which prevents anyone from dropping, altering or recreating a trigger or stored procedure if it has been used since the database was opened. This restriction has been removed again in version 2.0.1. Still, performing these operations on a live database is potentially risky and should only be done with the utmost care. CREATE VIEW Available in: DSQL, ESQL VIEW Per-column aliases supported in view definition Changed in: 2.1 Description: Firebird 2.1 and up allow the use of column aliases in the SELECT statement. You can alias none, some or all of the columns; each alias used becomes the name of the corresponding view column. Syntax (partial): Notes: CREATE VIEW viewname [] AS SELECT [, ...] FROM ... [WITH CHECK OPTION] ::= (colname [, colname ...]) ::= {source_col | expr} [[AS] colalias] • If the full column list is also present, specifying column aliases is futile as they will be overridden by the names in the column list. • The full column list used to be mandatory for views whose SELECT statement contains expression-based columns or identical column names. Now you can omit the full column list, provided that you alias such columns in the SELECT clause. Full SELECT syntax supported Changed in: 2.0 53
DDL statements Description: From Firebird 2.0 onward view definitions are considered full-fledged SELECT statements. Consequently, the following elements are (re)allowed in view definitions: FIRST, SKIP, ROWS, ORDER BY, PLAN and UNION. Note The use of a UNION within a view is currently only supported if you supply a column list for the view (this list is normally optional): create view vplanes (make, model) as select make, model from jets union select make, model from props union select make, model from gliders In Firebird 2.5, the column list will become optional also for views with UNIONs. PLAN subclause disallowed in 1.5, reallowed in 2.0 Changed in: 1.5, 2.0 Description: Firebird versions 1.5.x forbid the use of a PLAN subclause in a view definition. From 2.0 onward a PLAN is allowed again. Triggers on updatable views block auto-writethrough Changed in: 2.0 Description: In versions prior to 2.0, Firebird often did not block the automatic writethrough to the underlying table if one or more triggers were defined on a naturally updatable view. This could cause mutations to be performed twice unintentionally, sometimes leading to data corruption and other mishaps. Starting at Firebird 2.0, this misbehaviour has been corrected: now if you define a trigger on a naturally updatable view, no mutations to the view will be automatically passed on to the table; either your trigger takes care of that, or nothing will. This is in accordance with the description in the InterBase 6 Data Definition Guide under Updating views with triggers. Warning Some people have developed code that counts on or takes advantage of the prior behaviour. Such code should be corrected for Firebird 2.0 and higher, or mutations may not reach the table at all. View with non-participating NOT NULL columns in base table can be made insertable Changed in: 2.0 Description: Any view whose base table contains one or more non-participating NOT NULL columns is readonly by nature. It can be made updatable by the use of triggers, but even with those, all INSERT attempts into such views used to fail because the NOT NULL constraint on the base table was checked before the view trigger 54
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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
Page 14 and 15: Chapter 2 Reserved words and keywor
Page 16 and 17: LOCK LOG LOG10 LPAD MATCHED MATCHIN
Page 18 and 19: Chapter 3 Available in: DSQL, PSQL
Page 20 and 21: Example: select name, age, case upp
Page 22 and 23: Data types and subtypes • Partial
Page 24 and 25: Added in: 1.0, 1.5, 1.5.1, 2.0, 2.1
Page 26 and 27: Chapter 5 DDL statements The statem
Page 28 and 29: With a special attribute (case-sens
Page 30 and 31: DIFFERENCE FILE parameter Added in:
Page 32 and 33: CREATE DOMAIN Available in: DSQL, E
Page 34 and 35: Example: DDL statements create exce
Page 36 and 37: Syntax: Example: ALTER EXTERNAL FUN
Page 38 and 39: DDL statements -- the following que
Page 40 and 41: DDL statements PROCEDURE A stored p
Page 42 and 43: DDL statements Description: Firebir
Page 44 and 45: DDL statements NOT NULL in variable
Page 46 and 47: CREATE GENERATOR Available in: DSQL
Page 48 and 49: Better alternative: DROP SEQUENCE D
Page 50 and 51: ) DDL statements lastname varchar(2
Page 52 and 53: USING INDEX subclause Available in:
Page 54 and 55: ALTER COLUMN: SET DEFAULT Available
Page 56 and 57: UNIQUE constraints now allow NULLs
Page 58 and 59: Example: DDL statements create trig
Page 60 and 61: Multi-action triggers Added in: 1.5
Page 62 and 63: NOT NULL in variable declarations C
Page 66 and 67: DDL statements got a chance to put
Page 68 and 69: 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
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PSQL statements as declare variable
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Examples: PSQL statements thoroughl
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leave; end end c = 0; PSQL statemen
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Chapter 9 Available in: DSQL, PSQL
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Changed in: 2.0 Context variables D
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Context variables its execution was
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Context variables Description: OLD
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Chapter 10 Changed in: 2.0 Operator
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UNION as subselect Changed in: 2.0
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Chapter 11 Aggregate functions Aggr
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Chapter 12 Available in: DSQL, PSQL
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• If the argument is NULL, NULL i
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Result type: INTEGER or BIGINT Synt
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Result type: INTEGER Syntax: BIT_LE
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Internal functions This gives you c
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Available in: DSQL, PSQL Added in:
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Example: The equivalent CASE constr
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WEEK Bug alert Internal functions M
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Added in: 2.1 Internal functions De
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Internal functions • If x is nega
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Examples: Internal functions lpad (
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Internal functions This will return
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Internal functions overlay ('Goodby
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Internal functions Description: Cre
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Internal functions reverse ('Was it
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Added in: 2.1 Internal functions De
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Syntax: SINH (number) Important Int
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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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