Firebird 2.1 Language Reference Update

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Chapter 10 Changed in: 2.0 Operators and predicates NULL literals allowed as operands Description: Before Firebird 2.0, most operators and predicates did not allow NULL literals as operands. Tests or operations like “A NULL”, “B + NULL” or “NULL < ANY(...)” would be rejected by the parser. Now they are allowed almost everywhere, but please be aware of the following: The vast majority of these newly allowed expressions return NULL regardless of the state or value of the other operand, and are therefore worthless for any practicle purpose whatsoever. In particular, don't try to determine (non-)nullness of a field or variable by testing with “= NULL” or “ NULL”. Always use “IS [NOT] NULL”. Predicates: The IN, ANY/SOME and ALL predicates now also allow NULL literals where they were previously taboo. Here too, there is no practical benefit to enjoy, but the situation is a little more complicated in that predicates with NULLs do not always return a NULL result. For details, see the Firebird Null Guide, section Predicates. Available in: DSQL, ESQL, PSQL Text BLOB concatenation Changed in: 2.1 || (string concatenator) Description: Since Firebird 2.1 the concatenation operator supports BLOBs of any length and any character set. If a mixture of BLOBs and non-BLOBs is involved, the result is a BLOB. If both text and binary BLOBs are involved, the result is a binary BLOB. Result type VARCHAR or BLOB Changed in: 2.0, 2.1 Description: Before Firebird 2.0, the result type of string concatenations used to be CHAR(n). In Firebird 2.0 this was changed to VARCHAR(n). As a result, the maximum length of a concatenation outcome became 32765 117
Operators and predicates instead of 32767. In Firebird 2.1 and up, if at least one of the operands is a BLOB, the result is also a BLOB and the maximum doesn't apply. For non-BLOB concatenations the result is still VARCHAR(n) with a maximum of 32765 bytes. Overflow checking Changed in: 1.0, 2.0 Description: In Firebird versions 1.x, an error would be raised if the sum of the declared string lengths in a concatenation exceeded 65535 bytes, even if the actual result lay within the maximum string length of 32767 bytes. In Firebird 2.0 and up, the declared string lengths will never cause an error. Only if the actual outcome exceeds 32765 bytes (the new limit for concatenation results) will an error be raised. Available in: DSQL, ESQL, PSQL NULL literals allowed Changed in: 2.0 ALL Description: The ALL predicate now allows a NULL as the test value. Notice that this brings no practical benefits. In particular, a NULL test value will not be considered equal to NULLs in the subquery result set. Even if the entire set is filled with NULLs and the operator chosen is “=”, the predicate will not return true, but NULL. UNION as subselect Changed in: 2.0 Description: The subselect in an ALL predicate may now also be a UNION. Available in: DSQL, ESQL, PSQL NULL literals allowed Changed in: 2.0 ANY / SOME Description: The ANY (or SOME) predicate now allows a NULL as the test value. Notice that this brings no practical benefits. In particular, a NULL test value will not be considered equal to a NULL in the subquery result set. 118
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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
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DML statements ROWS can also be use
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DML statements COLLATE in variable
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The same call in ESQL (with obligat
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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 120 and 121: Chapter 9 Available in: DSQL, PSQL
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 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
Page 170 and 171: Syntax: SINH (number) Important Int
Page 174 and 175: Notes: Internal functions • If th
Page 176 and 177: 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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