WHEN is used to specify rows that meet a criteria such as: WHEN (EMP_SALARY < 90000). SELECT and SUBSET are invalid clauses and would cause an error.

Transcription

1 1. Suppose you have created a test version of a production table, and you want to to use the UNLOAD utility to extract the first 5,000 rows from the production table to load to the test version. Which keyword would you use in the UNLOAD statement? a. WHEN b. SELECT c. SAMPLE d. SUBSET The correct answer is C. You can specify SAMPLE n where n is the number of rows to unload. For example you can limit the unloaded rows to the first 5,000 by specifying: SAMPLE 5000 WHEN is used to specify rows that meet a criteria such as: WHEN (EMP_SALARY < 90000). SELECT and SUBSET are invalid clauses and would cause an error. Operations 2. Which of the following is NOT a valid value for the DDF subsystem parameter? a. YES b. NO c. COMMAND d. AUTO The correct answer is A. YES is not a valid value for DDF. NO means DDF is not to be loaded at DB2 startup, and it prevents it from being started by command. AUTO means that DDF will be automatically initialized and started when DB2 is started. The COMMAND value means DDF is to be initialized at DB2 startup and is prepared to receive the DSN1 START DDF command. 3. Which of the following is NOT a DB2 user address space? a. TSO b. CICS c. ADMIN d. WebSphere 1

2 The correct answer is C. There is no ADMIN address space. DB2 user address spaces can include any of the following: TSO Batch CICS IMS dependent region IMS control region WebSphere 4. Which bind option would you use to enable parallel processing to improve performance of a query? a. DEGREE(1) b. DEGREE(0) c. DEGREE(ANY) d. DEGREE(PARALLEL) The correct answer is C. The DEGREE option determines whether to attempt to run a query using parallel processing to maximize performance. Specifying DEGREE(1) prohibits parallel processing, while DEGREE(ANY) enables parallel processing. The values 0 and PARALLEL are invalid. 5. If you want to maximize data concurrency without seeing uncommitted data, which isolation level should you use? a. RR b. UR c. RS d. CS The correct answer is D (Cursor Stability). CURSOR STABILITY (CS) only locks the row where the cursor is placed, thus maximizing concurrency compared to RR or RS. REPEATABLE READ (RR) ensures that a query issued multiple times within the same unit of work will produce the exact same results. It does this by locking ALL rows that could affect the result, and does not permit any changes to the table that could affect the result. With READ STABILITY(RS), all rows that are returned by the query are locked. UNCOMMITTED READ (UR) is incorrect because it permits reading of uncommitted data and the question specifically disallows that. Data Concurrency 2

3 6. Which DB2 utility checks a tablespace for violations of check constraints and referential integrity? a. CHECK INTEGRITY b. CHECK INDEX c. CHECK LOB d. CHECK DATA The correct answer is D. CHECK DATA checks a tablespace for violations of check constraints and referential integrity, and provides a report of findings. CHECK INTEGRITY is not a valid DB2 command. CHECK INDEX determines whether indexes are consistent with the base tables that they index and reports inconsistencies. CHECK LOB checks for defects in the LOB table space and invalid LOB values, and reports findings. Operations 7. Which of the following is NOT an advantage of data sharing? a. Improves availability during outages. b. Provides scalable growth. c. Allows for flexible configurations. d. All of the above. The correct answer is D. All of the above are advantages of DB2 data sharing. 8. Which add-on DB2 product can improve performance for analytic workloads? a. DB2 Analytics Extender for z/os b. DB2 Analytics Accelerator for z/os c. DB2 Analytics Package for z/os d. DB2 Analytics Optimizer for z/os The correct answer is B. The DB2 Analytics Accelerator for z/os can improve performance for analytic workloads. The other choices are fictitious products. 3

4 9. Suppose you create a temporary table as follows: DECLARE GLOBAL TEMPORARY TABLE EMPLOYT LIKE EMPLOYEE NOT LOGGED IN USERSPACE1 Which of the following is NOT true about the temporary table EMPLOYT? a. When referencing table EMPLOYT in SQL, the table name must be qualified as SESSION.EMPLOYT. b. Constraints defined on table EMPLOYEE are also defined for table EMPLOYT. c. When the session ends, the temporary table EMPLOYT and any data in it are automatically deleted. d. All of the above are true statements about table EMPLOYT. The correct answer is B. When using the LIKE clause to create a temporary table, the implicit table definition includes only the column name, data type and nullability characteristic of each of the columns of the source table, and any column defaults. The temporary table does NOT have any unique constraints, foreign key constraints, triggers, indexes, table partitioning keys, or distribution keys. The other statements about the temporary table are true. When referencing table EMPLOYT in SQL, the table name must be qualified as SESSION.EMPLOYT. When the session ends, the temporary table EMPLOYT and any data in it are automatically deleted. 10. Which SYSIBM table can you query to find information about check constraints? a. SYSCHECKS b. CHECK_CONST c. SYSCON d. SYSVALIDVALS The correct answer is A. The SYSIBM.SYSCHECKS table contains the rules for check constraints. The other options are not valid table names. Working With Database Objects 4

5 11. Which ONE of the following actions will NOT cause a trigger to fire? a. INSERT b. LOAD c. DELETE d. MERGE The correct answer is B. The LOAD operation uses low-level access to populate the tables and triggers are not fired. A trigger is activated by an INSERT, UPDATE or DELETE of a record in a table. MERGE operations can also fire a trigger. 12. Which subsystem parameter determines whether DB2 will check authorizations or not? a. CHECK_AUTH b. AUTH_CHECK c. AUTH d. None of the above is valid. The correct answer is C. The AUTH subsystem parameter determines whether DB2 will check authorizations or not. Valid values are YES and NO. The default is YES. 13. When binding a package, what are the performance-guided recommended values for ISOLATION and CURRENTDATA for most applications? a. ISOLATION(UR) and CURRENTDATA(NO) b. ISOLATION(RR) and CURRENTDATA(YES) c. ISOLATION(CS) and CURRENTDATA(NO) d. ISOLATION(RS) and CURRENTDATA(YES) The correct answer is C. The recommended values for these options with most applications are: ISOLATION(CS) and CURRENTDATA(NO) These setting enable DB2 to acquire the least locks and to release the locks more quickly than all settings except ISOLATION(UR) - Uncomitted Read. Since this last setting allows the application to read uncommitted (dirty) data, it is not usually preferred. The RS and RR isolation levels acquire more locks and hold them longer, so they are not optimal for performance. 5

6 The CURRENTDATA(YES) setting means that (for local tables) the data upon which the cursor is positioned cannot change while the cursor is positioned on it, hence this setting causes more locks than the CURRENTDATA(NO) setting. 14. Given a subsystem named DB2X, which of the following address spaces provides support for remote data requests? a. DB2XDBM1 b. DB2XMSTR c. DB2XDIST d. IRLMPROC The correct answer is C. Given a subsystem named DB2X, the DB2XDIST address space provides support for remote requests. DB2XMSTR executes various system-related functions. DB2XDBM1 handles most data related requests. IRLMPROC controls DB2 locking. 15. What is a DB2 data sharing group? a. A collection of one or more DB2 subsystems that access shared DB2 data. b. A collection of shadow tables that reduce the workload on the operational tables. c. A collection of DB2 objects that are shared by multiple owners. d. A collection of objects that are referenced by two or more schema. The correct answer is A. A DB2 data sharing group is a group of one or more DB2 subsystems that can access shared DB2 data. 6