Firebird 2.1 Language Reference Update

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Available in: DSQL, PSQL Added in: <strong>2.1</strong> Internal functions RAND() Description: Returns a random number between 0 and 1. Result type: DOUBLE PRECISION Syntax: RAND () Important If the external function RAND is declared in your database, it will override the internal function. To make the internal function available, DROP or ALTER the external function (UDF). Note RDB$GET_CONTEXT() RDB$GET_CONTEXT and its counterpart RDB$SET_CONTEXT are actually predeclared UDFs. They are listed here as internal functions because they are always present – the user doesn't have to do anything to make them available. Available in: DSQL, ESQL, PSQL Added in: 2.0 Description: Retrieves the value of a context variable from one of the namespaces SYSTEM, USER_SESSION and USER_TRANSACTION. Result type: VARCHAR(255) Syntax: RDB$GET_CONTEXT ('', '') ::= SYSTEM | USER_SESSION | USER_TRANSACTION ::= A case-sensitive string of max. 80 characters The namespaces: The USER_SESSION and USER_TRANSACTION namespaces are initially empty. The user can create and set variables in them with RDB$SET_CONTEXT() and retrieve them with RDB$GET_CONTEXT(). The SYSTEM namespace is read-only. It contains a number of predefined variables, shown in the table below. 151
Internal functions Table 12.3. Context variables in the SYSTEM namespace DB_NAME Either the full path to the database or – if connecting via the path is disallowed – its alias. NETWORK_PROTOCOL The protocol used for the connection: 'TCPv4', 'WNET', 'XNET' or NULL. CLIENT_ADDRESS For TCPv4, this is the IP address. For XNET, the local process ID. For all other protocols this variable is NULL. CURRENT_USER Same as global CURRENT_USER variable. CURRENT_ROLE Same as global CURRENT_ROLE variable. SESSION_ID Same as global CURRENT_CONNECTION variable. TRANSACTION_ID Same as global CURRENT_TRANSACTION variable. ISOLATION_LEVEL The isolation level of the current transaction: 'READ COMMITTED', 'SNAPSHOT' or 'CONSISTENCY'. Return values and error behaviour: If the polled variable exists in the given namespace, its value will be returned as a string of max. 255 characters. If the namespace doesn't exist or if you try to access a non-existing variable in the SYSTEM namespace, an error is raised. If you poll a non-existing variable in one of the other namespaces, NULL is returned. Both namespace and variable names must be given as single-quoted, case-sensitive, non-NULL strings. Examples: select rdb$get_context('SYSTEM', 'DB_NAME') from rdb$database New.UserAddr = rdb$get_context('SYSTEM', 'CLIENT_ADDRESS'); insert into MyTable (TestField) values (rdb$get_context('USER_SESSION', 'MyVar')) See also: RDB$SET_CONTEXT() Note RDB$SET_CONTEXT() RDB$SET_CONTEXT and its counterpart RDB$GET_CONTEXT are actually predeclared UDFs. They are listed here as internal functions because they are always present – the user doesn't have to do anything to make them available. Available in: DSQL, ESQL, PSQL Added in: 2.0 152
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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
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 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
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 192 and 193: Changed in: 1.5, 1.5.2, 2.0 Better
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
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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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