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Using the multiple-row FETCH statement

The multiple-row FETCH statement can be used to retrieve multiple rows from a table orview with a single FETCH. The program controls the blocking of rows by the number of

rows requested on the FETCH statement !"#$%F has no effect&. The ma'imumnumber of rows that can be requested on a single fetch call is ()*+*. !nce the data is

retrieved, the cursor is positioned on the last row retrieved.

The multiple-row FETCH statement can be used with both serial and scrollable cursors.

The operations used to define, open, and close a cursor for a multiple-row FETCH remain

the same. !nly the FETCH statement changes to specify the number of rows to retrieveand the storage where the rows are placed.

fter each multiple-row FETCH, information is returned to the program through the

/0C. 1n addition to the /0C!$E and /0TTE fields, the /0E##$ provides

the following information2

/0E##$( contains the number of rows retrieved on the multiple-row FETCH

statement. 1f /0E##$( is less than the number of rows requested, then an error

or end-of-data condition occurred.

Step 1 :Declare a cursor

To define a result table to be accessed with a cursor, use the $EC0#E C3#!#

statement.

The $EC0#E C3#!# statement names a cursor and specifies a select-statement. The

select-statement defines a set of rows that, conceptually, make up the result table. For aserial cursor, the statement looks like this the F!# 34$TE !F clause is optional&2

EXEC SQL

DECLAREcursor-name CURSOR FOR

SELECTcolumn-1, column-2 ,...

FROMtable-name , ...

FOR UPDATE OFcolumn-2 ,...

END-EXEC.

For Scrollable CursorFor a scrollable cursor, the statement looks like this (the !E"E clause

is o#tional$%

EXEC SQL

DECLAREcursor-name DYNAMIC SCROLL CURSOR FOR

SELECTcolumn-1, column-2 ,...

FROMtable-name ,...

WHEREcolumn-1 & e'#ression ...

END-EXEC.

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The scrollable cursor FETCH statement looks like this2

EXEC SQL

FETCH RELATI&Einte3er

FROMcursor-name

INTO%host 0ariable-1, %host 0ariable-2 ...

END-EXEC.

Step 'a: Up(ate the %urre#t r!"

7hen your program has positioned the cursor on a row, you can update its data by usingthe 34$TE statement with the 7HE#E C3##E6T !F clause. The 7HE#E

C3##E6T !F clause specifies a cursor that points to the row you want to update. The

34$TE ... 7HE#E C3##E6T !F statement looks like this2

EXEC SQL

UPDATEtable-name

SETcolumn-1 & 0alue , column-2 & 0alue ... WHERE CURRENT OFcursor-name

END-EXEC.

Step '): Delete the %urre#t r!"

7hen your program has retrieved the current row, you can delete the row by using the

$E0ETE statement. To do this, you issue a $E0ETE statement designed for use with acursor< the 7HE#E C3##E6T !F clause specifies a cursor that points to the row you

want to delete. The $E0ETE ... 7HE#E C3##E6T !F statement looks like this2

EXEC SQLDELETE FROMtable-name

WHERE CURRENT OFcursor-name

END-EXEC.

Step *: Cl!se the Curs!r

1f you processed the rows of a result table for a serial cursor, and you want to use the

cursor again, issue a C0!E statement to close the cursor prior to re-opening it.

EXEC SQL

CLOSEcursor-name

END-EXEC.

1f you processed the rows of a result table and you do not want to use the cursor again,you can let the system close the cursor. The system automatically closes the cursor when2

C!==1T without H!0$ statement is issued and the cursor is not declared

using the 71TH H!0$ clause.

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#!00%C> without H!0$ statement is issued.

The ?ob ends.

The activation group ends and C0!/0C#@E6$CTA#4& was specified on

the precompile.

The first /0 program in the call stack ends and neither

C0!/0C#@E6$B!%& or C0!/0C#@E6$CTA#4& was specifiedwhen the program was precompiled.

The connection to the application server is ended using the $1C!66ECT

statement.

The connection to the application server was released and a successful C!==1T

occurred.

n @#37 C!66ECT occurred.

%ecause an open cursor still holds locks on referred-to-tables or views, you

should e'plicitly close any open cursors as soon as they are no longer needed.

D!namic Cursor

To issue a dynamic /0 statement, you must use the statement with either an EEC3TE

statement or an EEC3TE 1==E$1TE statement, because dynamic /0 statementsare not prepared at precompile time and therefore must be prepared at run time. The

EEC3TE 1==E$1TE statement causes the /0 statement to be prepared and rundynamically at program run time.

There are two basic types of dynamic /0 statements2 E0ECT statements and non-E0ECT statements. 6on-E0ECT statements include such statements as $E0ETE,

16E#T, and 34$TE.

To #uil" a "!namic S$% non-SE%ECT statement:

9. "erify that the /0 statement you want to build is one that can be rundynamically.

). %uild the /0 statement. 3se 1nteractive /0 for an easy way to build, verify,

and run your /0 statement.&

To run a dynamic /0 non-E0ECT statement2

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9. #un the /0 statement using EEC3TE 1==E$1TE, or 4#E4#E the /0

statement, then EEC3TE the prepared statement.

). Handle any /0 return codes that might result.

The following is an e'ample of an application running a dynamic /0 non-E0ECT

statement stmtstrg&2

EXEC SQL

E+ECUTE IMMEDIATE% stmtstr34

Usi#$ the PREPARE a#( E+ECUTE state,e#ts

5 non-SELEC statements contain no #arameter markers, the6 can be run

76namicall6 usin3 the EXECE 88EDE statement. !o9e0er, i5 the non-

SELEC statements ha0e #arameter markers, the6 must be run usin3 :"E:"E

an7 EXECE.

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