Returns the highest value for a value expression for all records specified by a record selection expression.
1 – Examples
The following programs demonstrate the use of the MAX function in an assignment statement. These programs: o Declare a host variable, latest_degree o Use the MAX function to compute the highest number stored in YEAR_GIVEN in the DEGREES relation o Assign this computed value to the host variable o Print an informational message and the value computed by the MAX function
1.1 – C Example
#include <stdio.h> DATABASE PERS = FILENAME "PERSONNEL"; main() { DECLARE_VARIABLE latest_degree SAME AS DEGREES.YEAR_GIVEN; READY PERS; START_TRANSACTION READ_ONLY; GET latest_degree = MAX D.YEAR_GIVEN OF D IN DEGREES; END_GET; printf ("Latest Degree was awarded in: %d\n", latest_degree); COMMIT; FINISH; }
1.2 – Pascal Example
program assignmax (input,output); DATABASE PERS = FILENAME 'PERSONNEL'; var DECLARE_VARIABLE latest_degree SAME AS DEGREES.YEAR_GIVEN; begin READY PERS; START_TRANSACTION READ_ONLY; GET latest_degree = MAX D.YEAR_GIVEN OF D IN DEGREES; END_GET; writeln ('Latest Degree was awarded in: ', latest_degree); COMMIT; FINISH; end.
2 – Format
(B)0[m q> [4mMAX[m qqqqqqqqqwq>qqqqqqqqqqqqqqqqqqwqqqqqqqqqqqqqqqqqqqqqqqqqk mq> handle-options qqj x x lqqqqqqqqqqqqqqqqqqqqqqqqqqqqq<qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqj x mqqqqqqqq> value-expr qqqq> [4mOF[m qqqq> rse qqqqqqqqqqqqq> (B)0[mhandle-options = q> ( qwqqqqqq> [4mREQUEST_HANDLE[m qqqqq> var qqqqqqqqwq> ) q> tqqqqqq> [4mTRANSACTION_HANDLE[m qqq> var qqqqqqqqu mqqqqqq> [4mREQUEST_HANDLE[m q> var q> , qqqqqqqk x lqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqj x mqqqq> [4mTRANSACTION_HANDLE[m q> var qqqqqqqqqqqj
2.1 – Format arguments
value-expr A value expression. A symbol or a string of symbols used to calculate a value. When you use a value expression in a statement, Oracle Rdb calculates the value associated with the expression and uses that value when executing the statement. rse A record selection expression. A phrase that defines specific conditions that individual records must meet before Oracle Rdb includes them in a record stream. handle-options A request handle, a transaction handle, or both. REQUEST_HANDLE var The REQUEST_HANDLE keyword followed by a host language variable. A request handle identifies a compiled Oracle Rdb request. If you do not supply a request handle explicitly, RDML associates a unique request handle for the compiled request. TRANSACTION_HANDLE The TRANSACTION_HANDLE keyword followed by var a host language variable. A transaction handle identifies a transaction. If you do not supply a transaction handle explicitly, RDML uses the default transaction handle.