Don't place decision to execute in the subroutine
perform get_start_end_date. form get_start_end_date. check not ( s_workdt[] is initial ). ...more processing... endform. instead do: If not ( s_workdt[] is initial ). perform get_start_end_date. endif.
Use CASE statement instead of IF...ELSEIF when possible (It is only possible in equality tests)
if t_bsid-maber = c_alumni_debit. ...do something... elseif t_bsid-maber = c_medical_debit. ...do something... else. ...do something else... endif. instead do: case t_bsid-maber. when c_alumni_debit. ...do something... when c_medical_debit. ...do something... when others. ...do something else... endcase.
Test most likely to fail first (specific to general)
if t_covp-vrgng = 'COIN'. " a document created in FI if t_covp-objnr = 'PR00003078'. " a specific cost object (wbs element) ...do something... endif. endif. instead do: if t_covp-objnr = 'PR00003078'. " a specific cost object (wbs element 6453100) if t_covp-vrgng = 'COIN'. " a document created in FI ...do something... endif. endif.
Test most likely to fail first (specific to general)
if t_covp-vrgng = 'COIN' and t_covp-objnr = 'PR00003078'. "FI doc and wbs 6453100 ...do something... endif. instead do: if t_covp-objnr = 'PR00003078' and t_covp-vrgng = 'COIN'. "6453100 and FI ...do something... endif.
Test most likely to succeed first (general to specific)
if t_covp-objnr = 'PR00003078' or t_covp-vrgng = 'COIN'. "6453100 or FI ...do something... endif. instead do: if t_covp-vrgng = 'COIN' or t_covp-objnr = 'PR00003078'. "FI or 6453100 ...do something... endif.
loop at t_bseg. select single name1 from kna1 into w_name where kunnr = t_bseg-kunnr. endloop. instead do: data: begin of t_kna1 occurs 0, kunnr like kna1-kunnr, name1 like kna1-name1, end of t_kna1. select kunnr name1 from kna1 into table t_kna1. sort t_kna1 by kunnr. loop at t_bseg. read table t_kna1 with key kunnr = t_bseg-kunnr binary search. if sy-subrc = 0. w_name = t_kna1-name1. endif. endloop.
read table t_vbap with key ps_psp_pnr = t_tab-pspnr binary search. t_vbap-kunnr = w_kunnr. modify table t_vbap index sy-tabix.
loop at t_vbak. select single kunnr into t_vbak-payer from vbpa where vbeln = t_vbak-vbeln and posnr = c_head_data " 000000 item indicates header and parvw = c_payer. " RG is payer if sy-subrc <> 0. message a056 with 'VBPA' t_vbak-vbeln. endif. modify t_vbak. endloop. " loop through contract headers and find payers instead do: field-symbols <f_vbak> like t_vbak. loop at t_vbak assigning <f_vbak>. select single kunnr into <f_vbak>-payer from vbpa where vbeln = <f_vbak>-vbeln and posnr = c_head_data " 000000 item indicates header and parvw = c_payer. " RG is payer if sy-subrc <> 0. message a056 with 'VBPA' <f_vbak>-vbeln. endif. endloop. " loop through contract headers and find payers
if not ( iw_current is initial ). <f_vbap>-current = <f_vbap>-current + iw_current. read table t_vbak key vbeln = <f_vbap>-vbeln binary search. * by definition header must exist if line item exists! Hence no return code check t_expenses-prime_contract = t_vbak-bstnk. " primary contract t_expenses-posid = <f_prps>-posid. " billable wbs t_expenses-matnr = w_matnr. " material t_expenses-kbetr = iw_current. " current expenses collect t_expenses. " current by wbs/contract/material endif. " are there dollars charged to this contract?
SORT tables BY fields
sort t_kna1. Instead sort t_kna1 by kunnr.
select name1 from kna1 into w_name up to 1 rows where kunnr = t_bseg-kunnr. instead do: select single name1 from kna1 into w_name where kunnr = t_bseg-kunnr. or: select single name1 ktokk from lfa1 into (w_vname1, w_ktokk) where kunnr = t_bseg-kunnr.
data: begin of t_kna1 occurs 0, kunnr like kna1-kunnr, name1 like kna1-name1, end of t_kna1. select kunnr name1 from kna1 into table t_kna1. "replaces contents of t_kna1
data: begin of t_proj occurs 0, pspnr like proj-pspnr, " internal project def. number objnr like proj-objnr, " PD + internal proj number end of t_proj. data: begin of t_prps occurs 0, objnr like prps-objnr, " WBS element object # PR+int rsn pspnr like prps-pspnr, " WBS element internal rsn posid like prps-posid, " WBS element external number stufe like prps-stufe, " hierarchy level (1 is top) fakkz like prps-fakkz, " billing indicator (X=yes) zbillt like prps-zbillt, " billing type (01=cost reimburs) psphi like prps-psphi, " number of project def. internal zend like prps-zend, " expiration date ztermcd like prps-ztermcd, " term code up like prhi-up, " parent WBS element internal budget like rpsco-wtp00, " auth. total on WBS element actual like rpsco-wtp00, " total expenditure on WBS revenue like rpsco-wtp00, " total revenue on WBS begbal like rpsco-wtp00, " begin balance on WBS end of t_prps. refresh t_prps. clear t_prps. loop at t_proj. select objnr pspnr posid stufe fakkz zbillt psphi zend ztermcd from prps into t_prps "place row into header of t_prps where psphi eq t_proj-pspnr "prps project = project rsn and zbillt eq p_billt. "billing type input param (01) append t_prps. "append header to body of table endselect. "notice no keyword table which is why the endselect if sy-subrc <> 0. write t_proj-pspnr to w_posid. "convert to wbs element ext # w_error = 'Project & with no WBS element'(002). replace '&' with w_posid(7) into w_error. write w_error. endif. endloop. "loop through all the billable projects
Instead of appending (as in above example) do the following (but make sure unique key is in select clause):
select objnr pspnr posid stufe fakkz zbillt psphi zend ztermcd "pspnr is unique from prps into table t_prps "place row into header of t_prps for all entries in t_proj "all billable projects in internal table where psphi eq t_proj-pspnr "prps project = project rsn and zbillt eq p_billt. "billing type input param (01)
If the select clause is not unique, it is the
equivalent of using a "select distinct". In other words duplicates
will not be selected.
data: begin of t_kna1 occurs 0, kunnr like kna1-kunnr, name1 like kna1-name1, end of t_kna1. select name1 from kna1 into corresponding fields of table t_kna1.
select shkzg wrbtr saknr "debit/credit indicator, amount, GL acct from bseg into table t_bseg for all entries in t_bkpf where belnr = t_bkpf-belnr and bukrs = 'CUR '.
1) This is the equivalent of saying "select distinct shkzg wrbtr saknr"
It will only pick up one line item if multiple line items appear with the same debit/credit indicator, amount and GL Account. If you want all occurrences of these you must have a select statement that includes the table's unique key, also called primary key. In the data dictionary (SE11) the fields belonging to the unique key are marked with an "X" in the key column. instead do: select bukrs belnr gjahr buzei shkzg wrbtr saknr "bseg unique key + d/c ind, amt, GL acct from bseg into table t_bseg for all entries in t_bkpf where belnr = t_bkpf-belnr and bukrs = 'CUR '.
2) FOR ALL ENTRIES IN...acts like a range table, so that if the "one" table is empty, all rows in the "many" table are selected.
if not t_proj[] is initial. select objnr pspnr posid stufe fakkz zbillt psphi zend ztermcd from prps into table t_prps for all entries in t_proj "all billable projects where psphi eq t_proj-pspnr "prps project = project rsn and zbillt eq p_billt. "billing type input param (01) endif. "if there are any projects
3) If the parent table (t_proj) is very large there is performance degradation
Instead loop through parent table(t_proj), appending to child table (t_prps) loop at t_proj. select objnr pspnr posid stufe fakkz zbillt psphi zend ztermcd from prps into t_prps "place row into header of t_prps where psphi eq t_proj-pspnr "prps project = project rsn and zbillt eq p_billt. "billing type input param (01) append t_prps. "append header to body of table endselect. "notice no keyword table which is why the endselect if sy-subrc <> 0. write t_proj-pspnr to w_posid. "convert to wbs element ext # w_error = 'Project & with no WBS element'(002). replace '&' with w_posid(7) into w_error. write w_error. endif. endloop. "loop through all the billable projects
where objnr = c_offset "OR000009999900 dummy int order and lednr = '00' "standard ledger and versn = '000'. "General Planning and wrttp = c_actual "04 actuals value type and gjahr =< gjahr "fiscal year and kstar = c_overrun "0000422342 cost overruns and beknz <> c_settlement. "A means a settlement
Delete from zzsupradr client specified where mandt = sy-mandt.
data t_name like is_name occurs 0 with header line. data t_prob like is_name occurs 0 with header line. 299 loop at t_name where room = space. 300 write: / t_name-name, t_name-room, t_name-cnt. 301 move t_name-name to t_prob-name. 302 move t_name-room to t_prob-room. 303 move t_name-cnt to t_prob-cnt. 304 append t_prob. 305 endloop. instead do: 299 loop at t_name where room = space. 300 write: / t_name-name, t_name-room, t_name-cnt. 301 append t_name to t_prob. 305 endloop.
* * internal table to rollup the following totals to billable wbs element: * expenditure, budget, revenue, wip (work in process, i.e. not billed), * overexpenditure & to be billed. unique key is psphi (project #), * posid (billable wbs element), pspnr (billable internal wbs number), * vbeln (sales doc # for sales order), * posnr (line item # for sales order), zend (expiration date on posid), * ztermcd (term code on posid), zspon (sponsor customer id), billreq * (billing request sales doc #) * data: begin of t_tab occurs 0, psphi like prps-psphi, " project internal number posid like prps-posid, " rollup external WBS element pspnr like prps-pspnr, " rollup WBS element internal rsn vbeln like vbap-vbeln, " SD order number posnr like vbap-posnr, " SD order item # zend like prps-zend, " expiration date for rollup wbs ztermcd like prps-ztermcd, " term code for rollup wbs zspon like prps-zspon, " customer ID billreq like vbap-vbeln, " Billing Request Sales Doc # total like rpsco-wtp00, " total expenditure budget like rpsco-wtp00, " authorized total revenue like rpsco-wtp00, " total revenue wip like rpsco-wtp00, " expense - revenue overex like rpsco-wtp00, " overexpenditure tobill like rpsco-wtp00, " wip - overex begbal like rpsco-wtp00, " beginning balance billed like rpsco-wtp00, " billing request doc total end of t_tab.
************************************************************************ * SYSTEM: CO * AUTHOR: Allan Davidson * DATE : June 1999 * TITLE : Change Supervisor/Addressee/Rooms/mail codes * PURPOSE : This report changes Supervisor, Addressee, * Supervisor room, Addressee room, or mailcode * of WBS-elements, cost center or orders. * This is a modified copy of ZCOCHNG with two major changes: * 1. MIT ID is used for searching instead of name. * 2. An interactive list is created, rather than a word * document, for checking updates prior to making them. * * There are two possible steps: * 1. Search possible WBS-elements, cost center or orders, * which are like the inputfield and display result in an * * interactive list. * 2. Update the cost objects from the interactive list. ************************************************************************ * AMENDMENTS: * VER DATE AUTHOR DESCRIPTION OF CHANGE * === ======== ========== ===================== ************************************************************************
*&---------------------------------------------------------------------* *& Form CALCULATE_ROLLUP_TOTALS *&---------------------------------------------------------------------* ************************************************************************ * Calculate wip (work in process), cost overruns, to be billed. * * If to be billed is zero delete from table. * * Get the sales order numbers to which the WBS elements are linked * * and report on any projects with wip but no sales order. * ************************************************************************ *----------------------------------------------------------------------* *----------------------------------------------------------------------*
loop at t_prps where tabid = w_posid. "problem wbs elements select distinct meinb kstar into table t_coep "collect unit meas. from coep "& cost elements from trans where lednr = '00' "encourage index coep_1 and objnr = t_prps-objnr "wbs object # and wrttp in r_wrttp "31, 03-12 actuals value types and versn = '000' "encourage index coep_1 and kstar in r_kstar_cosp. "expense cost elements check sy-subrc = 0. "expenses found for this wbs element continue otherwise get next wbs loop at t_coep. check t_coep-meinb = w_meinb. "problem unit of measurement ... endloop. "loop through cost elements and units of measurement endloop. "loop through wbs elements with potential problem instead do: loop at t_prps where tabid = w_posid. "problem wbs elements select distinct kstar into table t_kstar "collect potential from coep "problem expense cost elements where lednr = '00' "encourage index coep_1 and objnr = t_prps-objnr "wbs object # and wrttp in r_wrttp "31, 03-12 actuals value types and versn = '000' "encourage index coep_1 and kstar in r_kstar_cosp "expense cost elements and meinb = w_meinb. "problem unit of measurement check sy-subrc = 0. "problem expenses found for this wbs element continue otherwise get next wbs ... endloop. "loop through wbs elements with potential problem BUT MAKE SURE THAT THIS CONTINUES TO USE THE INDEX!
Use text elements for translatable text.
Use constants for non-translatable literals.
This sample code is a good example because it uses the text element (012) in
conjunction with the hard coded text.This documents the text element and provides
for the possibility of multi-language support.
constants: c_csks(4) value 'CSKS', " Cost centers
write: / c_csks, '-- # of rows need be updated:'(012), w_cnt.
*----------------------------------------------------------------------* * CALCULATE AUTHORIZED TOTAL PER WBS ELEMENT *----------------------------------------------------------------------* select wtp00 from rpsco into table t_rpsco "summarized budget where objnr = t_prps-objnr "PR+rsn wbs elem object and wrttp eq c_budget. "41 budget value type loop at t_rpsco. add t_rpsco-wtp00 to t_prps-budget. "total budget endloop. instead do: select sum( wtp00 ) from rpsco into t_prps-budget "summarized budget where objnr = t_prps-objnr "PR+rsn wbs elem object and wrttp eq c_budget. "41 budget value type
perform status_change using c_status. form status_change using value(p_c_status). ... endform.
loop at t_bseg. clear w_name. read table t_kna1 with key kunnr = t_bseg-kunnr binary search. if sy-subrc = 0. w_name = t_kna1-name1. endif. endloop.
loop at t_proj. select objnr pspnr posid stufe fakkz zbillt psphi zend ztermcd from prps into t_prps "place row into header of t_prps where psphi eq t_proj-pspnr "prps project = project rsn and zbillt eq p_billt. "billing type input param (01) append t_prps. "append header to body of table endselect. "notice no keyword table which is why the endselect if sy-subrc <> 0. write t_proj-pspnr to w_posid. "convert to wbs element ext # w_error = 'Project & with no WBS element'(002). replace '&' with w_posid(7) into w_error. write w_error. endif. "see below for explanation of why the return code is tested after endselect endloop. "loop through all the billable projects
Paraphrased from "Teach Yourself ABAP/4 in 21 Days" by Ken Greenwood (page 80):
If you have coded a select ... endselect, the value of sy-subrc must be tested after the endselect. "Why? The answer lies in the fact that the code between the select and endselect is executed once for each row returned from the database. If zero rows are returned from the database, the code between select and endselect is never executed. Therefore, you must code the test for sy-subrc after the endselect."
select vbeln "uses VBAK______A index from vbak into table t_vbak where vbeln in r_vbeln "billing request doc range '0070000000' - '0074999999' and erdat = max_datum "original run date and auart = c_zpsr "billing request ZPSR and vkorg = c_vkorg "sales org 1000 (sponsored programs) and ernam = t_zjobrun-uname. "user who ran original job if sy-subrc <> 0. clear w_samedate. "no bills were created exit. endif.
call transaction 'KB14' using t_bdctab mode 'N' messages into t_msgtab. if sy-subrc = 0. write: / t_doc-posid(8), 'Overexpenditure posting'(038), t_doc-doc01, 'reversed:'(039), sy-msgv1(10). commit work. else. reversal_trouble = 'X'. clear t_error. t_error-posid = t_doc-posid. t_error-vbeln = t_doc-doc01. perform process_errors. t_error-sortkey = c_error_reversed. append t_error. perform bdc_session_create using 'Reverse' 'KB14'. endif. "was the call transaction successful
(1) If a function module has no exceptions, sy-subrc will always be 0.
An example of such a function module is Z_R3_LIST_REPORT_SELECTIONS.
It is pointless to test a return code from such a function module and
the "pattern" button doesn't suggest it.
(2) If a function module always uses the construct, MESSAGE ...
RAISING ..., then it is handling exceptions with its own error
messages. Unless you want processing to continue even if an error is
encountered, you can drop the "EXCEPTIONS" section when you call the
function module. For instance, below is an example of redundant code
created using the "pattern" button.
call function 'SSF_FUNCTION_MODULE_NAME'
exporting
formname = p_form
importing
fm_name = w_fmname " generated function module
exceptions
no_form = 1
no_function_module = 2
others = 3.
if sy-subrc <> 0.
message id sy-msgid type sy-msgty number sy-msgno
with sy-msgv1 sy-msgv2 sy-msgv3 sy-msgv4.
endif.
This code should be changed to:
call function 'SSF_FUNCTION_MODULE_NAME'
exporting
formname = p_form
importing
fm_name = w_fmname. " generated function module
* function module is handling bad return code with appropriate error messages
The comment is helpful for the reviewer but should not be mandatory.
(3) If a function module uses the construct, RAISE ...., then it short
dumps when an exception is encountered! Regardless of whether you
want to continue or stop processing, you need to handle bad return
codes from such function modules to avoid a short dump. The following
code would cause a short dump in the unlikely event that p_domain is
invalid:
call function 'DDIF_DOMA_GET'
exporting
name = p_domain
langu = sy-langu
tables
dd07v_tab = t_dd07v.
On the other hand the following code, produced by the "pattern"
button, won't work because the system fields sy-msgid, sy-msgty,
sy-msgno etc, are not filled when the construct, RAISE ...., is used:
call function 'DDIF_DOMA_GET'
exporting
name = p_domain
langu = sy-langu
tables
dd07v_tab = t_dd07v
exceptions
illegal_input = 1
others = 2.
if sy-subrc <> 0.
message id sy-msgid type sy-msgty number sy-msgno
with sy-msgv1 sy-msgv2 sy-msgv3 sy-msgv4.
endif.
There are many valid ways to handle return code checking on a function
module like this. Three reasonable examples are:
call function 'DDIF_DOMA_GET'
exporting
name = p_domain
langu = sy-langu
tables
dd07v_tab = t_dd07v
exceptions
others = 1.
if sy-subrc <> 0.
p_desc = p_code.
exit.
endif.
call function 'DDIF_DOMA_GET'
exporting
name = p_domain
langu = sy-langu
tables
dd07v_tab = t_dd07v
exceptions
others = 1.
* sy-subrc will always be 0 because p_domain is always valid
The comment is helpful for the reviewer but should not be mandatory.
call function 'JOB_CLOSE'
exporting
jobname = my_job-jobname
jobcount = my_job-jobcount
strtimmed = c_yes
exceptions
cant_start_immediate = 1
invalid_startdate = 2
jobname_missing = 3
job_close_failed = 4
job_nosteps = 5
job_notex = 6
lock_failed = 7.
if sy-subrc eq 0.
* Job & number & started in background
message i180(26) with my_job-jobname my_job-jobcount.
else.
case sy-subrc.
when 1.
w_problem = 'Can not start immediate'(071).
when 2.
w_problem = 'Invalid start date'(070).
when 3.
w_problem = 'Jobname missing'(069).
when 4.
w_problem = 'Job close failed'(068).
when 5.
w_problem = 'Job no steps'(013).
when 6.
w_problem = 'Job notex'(010).
when 7.
w_problem = 'Lock failed'(007).
when others.
w_problem = sy-subrc.
endcase.
* System error: Termination in routine JOB & &
message e040(zz) with 'CLOSE'(014) w_problem.
endif.
if w_batch < 999.
lw_action = 'insert'(041).
zjobrun-mandt = sy-mandt.
zjobrun-pgnam = w_report_name.
w_batch = w_batch + 1.
zjobrun-batch = w_batch.
zjobrun-uname = sy-uname.
insert into zjobrun values zjobrun.
else.
lw_action = 'update'(042).
update zjobrun
set datum = lw_date
uzeit = lw_time
uname = sy-uname
reccount = 0
errcount = 0
cntrlrec = 0
credit = 0
debit = 0
errfile = ' '
review = ' '
text = ' '
where pgnam = w_report_name
and batch = w_batch.
endif.
if sy-subrc = 0.
commit work.
else.
* Required update of table ZJOBRUN failed
message i032 with lw_action sy-subrc.
stop.
endif.
open dataset w_fname for input in text mode " get input data
message lw_msg. " any errors place here
if sy-subrc <> 0.
message i002 with lw_msg.
stop.
endif. read dataset w_fname into lw_row.
if sy-subrc <> 0. " end of file reached
exit. " leave do loop
endif. loop at lt_files.
delete dataset lt_files-name.
if sy-subrc = 0.
t_body-line = lt_files-name.
append t_body.
endif.
endloop. form write_unix_file.
open dataset myfile for output in text mode.
if sy-subrc <> 0.
write sy-subrc to w_subrc.
concatenate 'Problem opening' myfile 'to UNIX.' w_subrc
into t_body-line separated by space.
append t_body.
concatenate p_maber 'Invoice Load problems encountered'
into w_subject.
perform send_mail.
message a000 with 'Problem opening UNIX.' sy-subrc." stop processing because transfer will short dump
endif. "problem with open
loop at t_invoice.
transfer t_invoice to myfile.
endloop. "loop through invoices
close dataset myfile.
Example 1: Dates being used in a BDC session or Call Transaction
data: w_bldat(10), "doc date - string conversion w_budat(10), "posting date - string conversion d_bldat like sy-datum, "doc date - today's day d_budat like sy-datum. "posting date - last day of month d_bldat = sy-datum. "doc date call function 'RP_LAST_DAY_OF_MONTHS' exporting day_in = d_bldat importing last_day_of_month = d_budat exceptions day_in_no_date = 1. if sy-subrc = 0. write d_bldat to w_bldat. "WRITE uses conversion exit to format date write d_budat to w_budat. "allows for correct user defaults endif. perform dynpro using: 'X' 'SAPMF05A' '0100', ' ' 'BKPF-BLDAT' w_bldat, "07/09/1999 if user's defaults are mm/dd/yyyy ' ' 'BKPF-BUDAT' w_budat, "07/31/1999 ' ' 'BKPF-BLART' w_blart, "doc type from zardiv ' ' 'BKPF-BUKRS' w_bukrs, "company code CUR ' ' 'BKPF-WAERS' w_waers, "currency USD ' ' 'BKPF-MONAT' w_monat, "POST PERIOD ' ' 'RF05A-NEWBS' w_bschl_deb, "customer debit posting key ' ' 'RF05A-NEWKO' cur_id. "customer ID
data w_date like sy-datum. "used to build defaults parameters: p_start like bsid-zfbdt default '', "begin baseline date p_end like bsid-zfbdt default ''. "end baseline date initialization. w_date = sy-datum. w_date+6(2) = '01'. w_date = w_date - 1. w_tdate = w_date. w_date+6(2) = '01'. w_fdate = w_date. if sy-batch eq ' '. p_end = w_tdate. "do not WRITE w_tdate to p_end! p_start = w_fdate. "19990601 actual 06/01/1999 displays 1//19/06/0 if WRITE had been used endif.
parameters: p_date like sy-datum. initialization. p_date = sy-datum. "do not WRITE sy-datum to p_date! start-of-selection. submit zzard036 with p_datum = p_date and return. "submits with value 19990709 REPORT ZZARD036. parameters: p_datum like sy-datum. "receives 19990709 start-of-selection. write: / 'called program:', p_datum. "the proper formatting occurs here on write 07/09/1999
data: begin of t_vbrk occurs 0, vbeln like vbrk-vbeln, " bill doc number xblnr like vbrk-xblnr, " audit voucher number fkdat like vbrk-fkdat, " FI posting date zuonr like vbrk-zuonr, " prime contract number kunrg like vbrk-kunrg, " payer netwr like vbrk-netwr, " current billed amount contract like vbak-vbeln, " SAP prime contract srv_from like vbrk-fkdat, " begin service date cumulative like vbrk-netwr, " cumulative billed budget like zmiprdetail-program_amount, " funded amount end of t_vbrk. constants: c95(2) type c value '95', " 95 contract c1995(5) type c value 'F1995', " 1995 prime contract c20(3) type c value 'F20'. " contracts in 21st cent perform find_prime_contract using <f_vbrk>-zuonr+7(2) changing <f_vbrk>-contract. form find_prime_contract using p_year type c " note that you can't specify length changing p_contract like vbak-vbeln. if p_year = c95. " '95' p_contract = c1995. " 'F1995' else. concatenate c20 p_year into p_contract. " F2000, F2005... endif. endform. " find_prime_contract