Assigns values from data records in a record stream to host
language variables in a program using the RDBPRE preprocessor
(for BASIC, COBOL, and FORTRAN). You cannot use GET in RDO.
Example:
&RDB& FOR E IN EMPLOYEES
&RDB& GET
&RDB& LAST-NAME = E.LAST_NAME;
&RDB& FIRST-NAME = E.FIRST_NAME;
&RDB& MIDDLE-INITIAL = E.MIDDLE_INITIAL
&RDB& END_GET
&RDB& END_FOR
1 – More
If you have invoked a database, you have the necessary privileges
to use the GET statement.
In RDBPRE programs, you can use the GET statement in three ways:
o When you establish a record stream with the FOR or START_
STREAM statement, you use the GET statement to assign values
from the current record in the stream to variables in your
program. In the case of START_STREAM, you also need FETCH to
indicate the current record in the stream.
o You can use GET alone, without a FOR or FETCH statement, to
retrieve the result of a statistical function. The record
stream is formed by the record selection expression within the
statistical expression.
o Or you can use GET...RDB$DB_KEY in a STORE...END_STORE block
to retrieve the database key of the record just stored.
Example:
&RDB& STORE E IN EMPLOYEES USING E.EMPLOYEE_ID = 15231;
&RDB& E.LAST_NAME = "Smith";
&RDB& GET MY_DB_KEY = E.RDB$DB_KEY;
&RDB& END_GET
&RDB& END_STORE
(MY_DB_KEY is a user-defined host language variable.)
You cannot use the concatenation operation in a GET statement.
NOTE
Use the GET statement only in RDBPRE programs. RDO uses the
PRINT statement to display values on the terminal.
2 – Format
(B)0[m[4mGET[m qwqqqqqqqqq>qqqqqqqqqwqqqqwqqqqqqqq>qqqqqqwqqqk
mq> handle-options qj mq> on-error qqj x
lqqqqqqqqqqqqqqqqqqqqqqqqqq<qqqqqqqqqqqqqqqqqqqqqqj
mqwq> get-item qqwqq> [4mEND_GET[m qq>
mqqqqq ; <qqqqqqj
2.1 – More
If you list a field for which the value is null, and there is
a MISSING_VALUE clause for that field, Oracle Rdb supplies the
missing value. If there is no MISSING_VALUE clause, and nulls are
allowed, then Oracle Rdb supplies zeros for numeric fields, blanks
for text fields, and the OpenVMS base date and time (17-NOV-1858
00:00:00.00) for date fields.
2.2 – handle-options
(B)0[mhandle-options =
qq> ( qwq> [4mREQUEST_HANDLE[m qqq> var qqqqqqqqqqqqqqqqqqqqqqqqqqqwq> ) qq>
tq> [4mTRANSACTION_HANDLE[m qqq> var qqqqqqqqqqqqqqqqqqqqqqqu
mq> [4mREQUEST_HANDLE[m q> var , [4mTRANSACTION_HANDLE[m q> var qj
2.2.1 – REQUEST_HANDLE
A keyword followed by a host language variable. A request handle
points to the location of a compiled Oracle Rdb request. If you
do not supply a request handle explicitly, Oracle Rdb associates a
default request handle with the compiled request. Your must use
a request handle when you want to make an identical query to two
different databases.
In Callable RDO, use !VAL as a marker for host language
variables.
You can put parentheses around the host language variable name.
2.2.2 – TRANSACTION_HANDLE
A keyword followed by a host language variable. A transaction
handle identifies each instance of a transaction. If you do not
declare the transaction handle explicitly, Oracle Rdb attaches an
internal identifier to the transaction.
In Callable RDO, use !VAL as a marker for host language
variables.
You can put parentheses around the host language variable name.
Normally, you do not need to use this argument. The ability to
declare a transaction handle is provided for compatibility with
other database products and future releases of Oracle Rdb.
2.3 – on-error
(B)0[m[4mON[m [4mERROR[m qwq> statement qwq> [4mEND_ERROR[m
mqqqqqqqq<qqqqqj
on-error
The ON ERROR clause. This clause specifies the action to be taken
if an Oracle Rdb error occurs during the GET operation. Request HELP
for ON_ERROR for more information.
2.4 – get-item
(B)0[mget-item =
qqqqqqwq> host-variable = value-expr qqqqqqqqqqqqqqqqwqqq>
tq> host-variable = statistical-expr qqqqqqqqqqu
mq> record-descr = context-var . * qqqqqqqqqqqj
Includes an assignment statement specifying a host language
variable and a database value. The value is assigned to the
host language variable from the Oracle Rdb value expression or
statistical expression.
2.4.1 – host-variable
A valid variable name declared in the host language program. Ask
for HELP on Value_expr for more information.
2.4.2 – statistical-expr
A statistical expression. A statistical expression calculates
values based on a value expression for every record in a record
stream. Ask for HELP on Value_expr for more information.
2.4.3 – value-expr
A valid Oracle Rdb value expression. Ask for HELP on Value_expr for
more information.
3 – Examples
Example 1
The following COBOL example retrieves values from named fields in
a relation:
&RDB& START_TRANSACTION READ_WRITE
&RDB& FOR E IN EMPLOYEES
&RDB& GET
&RDB& LAST-NAME = E.LAST_NAME;
&RDB& FIRST-NAME = E.FIRST_NAME;
&RDB& MIDDLE-INITIAL = E.MIDDLE_INITIAL
&RDB& END_GET
&RDB& END_FOR
&RDB& COMMIT
This code fragment retrieves field values from each record in
the EMPLOYEES relation. It assumes that the program has declared
the three host language variables, LAST-NAME, FIRST-NAME, and
MIDDLE-INITIAL, with the appropriate data types.
Example 2
The following set of statements performs a join of two relations
and uses GET to retrieve a value from each:
&RDB& START_TRANSACTION READ_WRITE
&RDB& FOR JH IN JOB_HISTORY CROSS D IN DEPARTMENTS
&RDB& OVER DEPARTMENT_CODE
&RDB& WITH JH.JOB_END MISSING
&RDB& GET
&RDB& ID_NUMBER = JH.EMPLOYEE_ID;
&RDB& DEPT-NAME = D.DEPARTMENT_NAME
&RDB& END_GET
&RDB& END_FOR
&RDB& COMMIT
Example 3
The following BASIC code fragment retrieves the result of a
statistical function:
INPUT "State: ", STATE
&RDB& START_TRANSACTION READ_ONLY
&RDB& GET
&RDB& NUMBER-EMPLOYEES = COUNT OF E IN EMPLOYEES
&RDB& WITH E.STATE = STATE
&RDB& END_GET
PRINT "Number of employees in "; &
STATE; " is "; NUMBER-EMPLOYEES
&RDB& COMMIT
This statement retrieves the number of employees who live in the
specified state and assigns that number to the variable NUMBER-
EMPLOYEES.
Example 4:
The following RDBPRE program segment uses GET...RDB$DB_KEY within
a STORE...END_STORE block to retrieve into a host language
variable the database key of the record about to be stored by
the STORE statement.
&RDB& STORE E IN EMPLOYEES USING E.EMPLOYEE_ID = 15231;
&RDB& E.LAST_NAME = "Smith";
&RDB& GET MY_DB_KEY = E.RDB$DB_KEY;
&RDB& END_GET
&RDB& END_STORE
(MY_DB_KEY is a user-defined host language variable.)