👁 0
Q: What is UDF (User Defined Function)?
Answer:
UDF extends SQL with custom functions. CREATE FUNCTION name(params) RETURNS type AS BEGIN logic END. Scalar returns single value. Table function returns rows. Use in SELECT, WHERE like built-in functions.
👁 0
Q: What causes S0C7 abend and how to fix it?
Answer:
S0C7 (Data Exception) occurs when non-numeric data is used in numeric operations. Common causes: uninitialized fields, incorrect data from files, wrong REDEFINES. Fix by: initializing variables, validating input data, using INSPECT/NUMVAL functions, checking file data quality.
👁 0
Q: How to use EXPLAIN tables?
Answer:
PLAN_TABLE primary output. DSN_STATEMNT_TABLE for cost. DSN_FUNCTION_TABLE for functions. INSERT EXPLAIN before statement. Query tables after. PLANNO, ACCESSTYPE, MATCHCOLS important columns.
👁 0
Q: How to handle EBCDIC/ASCII conversion?
Answer:
COBOL on mainframe uses EBCDIC natively. For ASCII conversion: use INSPECT CONVERTING, or file translation (JCL), or LE functions. NATIONAL-OF and DISPLAY-OF for Unicode. Different collating sequences affect SORT and comparisons.
👁 0
Q: How to handle date arithmetic?
Answer:
DATE + n DAYS adds days. DATE - n MONTHS subtracts months. DAYS(date2) - DAYS(date1) gives day count. DATEDIFF function available. TIMESTAMPDIFF for time differences. DATE/TIME functions for extraction.
👁 0
Q: What is EXEC CICS SEND CONTROL?
Answer:
SEND CONTROL sends control functions. EXEC CICS SEND CONTROL ERASE FREEKB. Clears screen, unlocks keyboard. No map or data. Prepare terminal for next operation.
👁 0
Q: How to use window functions?
Answer:
ROW_NUMBER() OVER (PARTITION BY col ORDER BY col2). RANK, DENSE_RANK for rankings. SUM/AVG/COUNT OVER for running totals. PARTITION BY groups within result. ORDER BY within partition. Powerful analytics.
👁 0
Q: How to use intrinsic functions?
Answer:
COBOL-85 intrinsic functions: FUNCTION LENGTH(field), FUNCTION CURRENT-DATE, FUNCTION UPPER-CASE(field), FUNCTION NUMVAL(field), FUNCTION MOD(a,b), FUNCTION INTEGER-OF-DATE(date). Use in expressions or with COMPUTE. Return values only, no side effects.
👁 0
Q: Explain ENTRY statement
Answer:
ENTRY creates alternate entry point in subprogram. ENTRY 'ALTNAME' USING params. Called program appears under different name. Useful for multiple functions in one load module. Each ENTRY has own parameters. Not standard-use carefully.
👁 0
Q: Explain DFSORT utility
Answer:
DFSORT sorts/merges files. SYSIN has SORT FIELDS=(1,10,CH,A). SORTIN=input, SORTOUT=output. Options: INCLUDE/OMIT for filtering, OUTREC/INREC for reformatting, SUM for summarization. ICETOOL provides extended functions.