Jump-Start Embedded SQL into RPG Presented by: Robert Arce

Jump-Start embedded SQL into RPG by Robert Arce Why SQL in RPG? Useful for ad hoc retrieval and update Easy manipulation of data SQL alone may not provide logic capabilities to perform required operations SQL has no user interface ad hoc statements can be complex sorting possibilities are enhanced by SQL

Jump-Start embedded SQL into RPG by Robert Arce SQL embedded types Static statements – structure of the statement does NOT change Static “select into” statements Dynamic Statements Cursors – to handle multiple retrieves

Jump-Start embedded SQL into RPG by Robert Arce SQL source type SQLRPG DB2/400 Query Manager RPG SQLRPGLE DB2 Query Manager RPG/400 Integrated Language Environment

Jump-Start embedded SQL into RPG by Robert Arce Create SQL ILE RPG Object CRTSQLRPGI Precompiles SQL statements creates RPGLE source file in QTEMP/QSQLTEMP1 (ToSrcFile option) Create Bound RPG program CRTBNDRPG Voila! you have a program

Jump-Start embedded SQL into RPG by Robert Arce Precompiler Directives Only one SQL statement C /exec sql --open sql code C+ update CUSMS C+ set CMREPS=233 C+ where CMREPS=5 C/ end-exec -- close sql code

Jump-Start embedded SQL into RPG by Robert Arce Host Variables RPG program variables are use within the SQL statements C /exec sql --open sql code C+ update CUSMS C+ set CMREPS= : newslsrep C+ where CMREPS= : oldslsrep C/ end-exec -- close sql code

Jump-Start embedded SQL into RPG by Robert Arce Indicator Variable ~ Null Indicator variable can optionally be coded after the host variable Two ways to declare Indicator variable: Dindnul_1 s 5i 0 Dindnul_2 s 4b 0 Assign negative (-1) as null or positive (0) as not null

Jump-Start embedded SQL into RPG by Robert Arce Indicator Variable C+ set SHIPTO=:newshipto :indship Same as: if indship = -1 SHIPTO = null else SHIPTO = newshipto endif

Jump-Start embedded SQL into RPG by Robert Arce Select Into ONLY retrieve ONE row or NADA! Into clause must list one host variable for each column in the select list Optionally and is suggested to use an indicator variable per each row Can select all fields “*” and assign them into the proper Data structure sqlstt = '21000‘  more than one row

Jump-Start embedded SQL into RPG by Robert Arce Select Into * Set host variables C customer= * C/exec sql C+ select CMCSNO, --customer number C+ CMCSNM, --customer name C+ CMDFSH --default shipto C+ into :csCMCSNO, C+ :csCMCSNM, C+ :csCMDFSH :inCMDFSH C+ from CUSMS C+ where CMCSNO=:customer C/end-exec

Jump-Start embedded SQL into RPG by Robert Arce Dynamic SQL Construct in string variables on the fly Execute immediate vs Prepare and execute Prepare takes extra time building statement but execution runs faster Parameter markers ‘?’  define in the Using clause with one host variable per marker

Jump-Start embedded SQL into RPG by Robert Arce Dynamic execute immediate * Assign SQL statement dynsqlstm='delete from CUSMS where '+ 'CMCSNM LIKE '+'''%CAR%''‘ * default when create pgm COMMIT =*CHG C/exec sql set option commit=*none C/end-exec C/exec sql C+ execute immediate :dynsqlstm C/end-exec

Jump-Start embedded SQL into RPG by Robert Arce Dynamic Prepare-execute Prepare Statement-Name from :host-variable C/exec sql --Part 1 C+ prepare dltcuscar C+ from :dynsqlstm C/end-exec * C if sqlstt = '00000' C/exec sql -- Part 2 C+ execute dltcuscar C/end-exec

Jump-Start embedded SQL into RPG by Robert Arce Dynamic Prepare-Parameter Marker dynsqlstm='delete from CUSMS where CMCSNM like ?' C/exec sql C+ prepare dltcustcar C+ from :dynsqlstm C/end-exec C if sqlstt = '00000' C eval namelike ='%CAR%‘ * C/exec sql C+ execute dltcustcar C+ using :namelike C/end-exec

Jump-Start embedded SQL into RPG by Robert Arce Cursors Cursors open more than one row Is based on Select statements Allow you to do data manipulation Sorts Sums Use Host Variable for sorts and selections Declare as read-only or updatable

Jump-Start embedded SQL into RPG by Robert Arce Cursors Declare cursor Open the cursor Fetch – like read records (rows) from cursor (optionally update or delete the most recently fetched record) Close cursor (cursor must be open)

Jump-Start embedded SQL into RPG by Robert Arce Cursor - Declare C/exec sql C+ declare custcursor cursor C+ for select CMCSNO, CMCSNM, CMDFSH C+ from CUSMS C+ where CMCSNM like :namelike C+ order by :custsort C+ for read only C/end-exec

Jump-Start embedded SQL into RPG by Robert Arce Cursor - Open Host variables are evaluated only when the cursor is open * sets values for the host variables C eval namelike = '%CAR%' C eval custsort = 'CMCSNO' C/exec sql C+ open custcursor C/end-exec

Jump-Start embedded SQL into RPG by Robert Arce Cursor - Fetch C dow morerows C/exec sql C+ Fetch Next C+ from custcursor C+ into :csCMCSNO, C+ :csCMCSNM, C+ :csCMDFSH C/end-exec

Jump-Start embedded SQL into RPG by Robert Arce Cursors - Update In the declare cursor statement replace: “for read only” by “for update of CMREPS” After the fetch do the update: C/exec sql C+ update CUSMS C+ set CMREPS=:newslsrep C+ where current of custcursor --name of the cursor C/end-exec

Jump-Start embedded SQL into RPG by Robert Arce Cursor - Dynamic C/exec sql C+ declare custcursor cursor C+ for selcustcar C/end-exec * Asssign sql to host variable: sqlstm='select CMCSNO,CMCSNM,CMDFSH '+ 'from CUSMS ' + 'where CMCSNM like ? ' + 'order by CMCSNO'

Jump-Start embedded SQL into RPG by Robert Arce Cursor - Dynamic C/exec sql C+ prepare selcustcar C+ from :dynsqlstm C/end-exec C if sqlstt ='00000' * sets parameter marker value C eval namelike='%CAR%' C/exec sql C+ open custcursor C+ using :namelike C/end-exec

Jump-Start embedded SQL into RPG by Robert Arce Fetch Position Next - Prior First - Last Before  before the first row After  after the last row Current  no change in position Relative n   negative ~ previous  positive ~ next

Jump-Start embedded SQL into RPG by Robert Arce references DB2 UDB for iSeries SQL programming c2924/index.htm?info/sqlp/rbafymst02.htm SQL/400 developer’s guide by Paul Conte and Mike Cravitz