Firebird 2.1 Language Reference Update

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Changed in: 1.5, 1.5.2, 2.0 Better alternative: Internal function TRIM() External functions (UDFs) Description: Returns the input string with any leading space characters removed. In new code, you are advised to use the internal function TRIM instead, as it is both more powerful and more versatile. Result type: VARCHAR(n) Syntax (unchanged): ltrim (str) Declaration: Notes: DECLARE EXTERNAL FUNCTION ltrim CSTRING(255) NULL RETURNS CSTRING(255) FREE_IT ENTRY_POINT 'IB_UDF_ltrim' MODULE_NAME 'ib_udf' The above declaration is from the file ib_udf2.sql. The NULL after the argument is an optional addition that became available in Firebird 2. If the argument is declared with the NULL keyword, the engine will pass a NULL argument value unchanged to the function. This leads to a NULL result, which is correct. Without the NULL keyword (your only option in pre-2.0 versions), NULL is passed to the function as an empty string and the result is an empty string as well. For more information about passing NULLs to UDFs, see the note at the end of this book. • Depending on how you declare it (see CSTRING note), this function can accept and return strings of up to 32767 characters. • Before Firebird 2.0, the result type was CHAR(n). • In Firebird 1.5.1 and below, the default declaration used CSTRING(80) instead of CSTRING(255). • In Firebird 1.0.x, this function returned NULL if the input string was either empty or NULL. Library: ib_udf Added in: IB Better alternative: Internal function MOD() mod Description: Returns the remainder of an integer division. Result type: DOUBLE PRECISION Syntax: mod (a, b) 181
Declaration: External functions (UDFs) DECLARE EXTERNAL FUNCTION mod INTEGER, INTEGER RETURNS DOUBLE PRECISION BY VALUE ENTRY_POINT 'IB_UDF_mod' MODULE_NAME 'ib_udf' Library: fbudf Added in: 1.0 (Win), 1.5 (Linux) Better alternative: Internal function NULLIF() *nullif Description: The four *nullif functions – for integers, bigints, doubles and strings, respectively – each return the first argument if it is not equal to the second. If the arguments are equal, the functions return NULL. Result type: Varies, see declarations. Syntax: inullif (int1, int2) i64nullif (bigint1, bigint2) dnullif (double1, double2) snullif (string1, string2) As from Firebird 1.5, use of the internal function NULLIF is preferred. Declarations: Warnings • These functions return NULL when the second argument is NULL, even if the first argument is a proper value. This is a wrong result. The NULLIF internal function doesn't have this bug. • i64nullif and dnullif will return wrong and/or bizarre results if it is not 100% clear to the engine that each argument is of the intended type (NUMERIC(18,0) or DOUBLE PRECISION). If in doubt, cast them both explicitly to the declared type (see declarations below). DECLARE EXTERNAL FUNCTION inullif INT BY DESCRIPTOR, INT BY DESCRIPTOR RETURNS INT BY DESCRIPTOR ENTRY_POINT 'iNullIf' MODULE_NAME 'fbudf' DECLARE EXTERNAL FUNCTION i64nullif NUMERIC(18,4) BY DESCRIPTOR, NUMERIC(18,4) BY DESCRIPTOR RETURNS NUMERIC(18,4) BY DESCRIPTOR ENTRY_POINT 'iNullIf' MODULE_NAME 'fbudf' DECLARE EXTERNAL FUNCTION dnullif DOUBLE PRECISION BY DESCRIPTOR, DOUBLE PRECISION BY DESCRIPTOR RETURNS DOUBLE PRECISION BY DESCRIPTOR ENTRY_POINT 'dNullIf' MODULE_NAME 'fbudf' 182
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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
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DML statements Aggregate functions
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Syntax: Example: Notes: ::= DML
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DML statements select d.dept_no, d.
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DML statements FIRST and SKIP are b
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DML statements select strlen(lastna
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DML statements Description: A natur
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DML statements • Only non-negativ
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Example: DML statements plan (MyTab
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UNIONs in subqueries Changed in: 2.
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Restrictions DML statements • The
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DML statements Description: Limits
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Chapter 7 Available in: DSQL Added
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Transaction control statements If t
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Transaction control statements •
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Chapter 8 PSQL statements PSQL - Pr
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PSQL statements • If sql_datatype
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Warning PSQL statements If you chan
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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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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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• 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
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
Page 178 and 179: Declaration: External functions (UD
Page 180 and 181: Library: ib_udf Changed in: 1.0, 2.
Page 182 and 183: Better alternative: Internal functi
Page 184 and 185: External functions (UDFs) Descripti
Page 186 and 187: Syntax: cot (angle) Declaration: Ex
Page 188 and 189: Declaration: External functions (UD
Page 190 and 191: Library: ib_udf Added in: IB Change
Page 194 and 195: External functions (UDFs) DECLARE E
Page 196 and 197: See sright. Library: fbudf Added in
Page 198 and 199: Notes: External functions (UDFs) Fo
Page 200 and 201: Syntax: sign (number) Declaration:
Page 202 and 203: Library: fbudf Added in: 1.0 (Win),
Page 204 and 205: Notes: External functions (UDFs) th
Page 206 and 207: Better alternative: Internal functi
Page 208 and 209: Appendix A: Notes Character set NON
Page 210 and 211: Table A.1. How TPB settings affect
Page 212 and 213: Notes A note on CSTRING parameters
Page 214 and 215: Notes Maximum number of indices in
Page 216 and 217: Document History DDL statements ::
Page 218 and 219: Document History Internal functions
Page 220: Appendix C: License notice The cont
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Firebird 2.1 Language Reference Update

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