LOOPSELECT num_credits INTO v_numcredits FROM classesWHERE dept=123 and course=101;UPDATE studentsSET current_credits=current_credits+v_numcreditsWHERE CURRENT OF X;END LOOPCOMMIT;END;
Latest Answer: When referencing the current row from an explicit cursor, we use 'WHERE CURRENT OF'. it allows us to apply updates and deletes to the row currently ...
No.
Latest Answer: No, directly we cannot use 'commit' inside the trigger.We have to use pragma Autonomous Transaction to issue commit inside a trigger. ...
Self join-Its a join foreign key of a table references the same table. Outer Join--Its a join condition used where One can query all the rows of one of the tables in the join condition even though they
Latest Answer: Please let me know various joins available and description for every joinRegards,sireesha ...
Latest Answer: Yes it possible to insert/update/delete data for CLOB, BLOB, NCLOB columns. Now how to do it. 1. Suppose if you are using JAVA applications to modify the database columns, then you have to open streaming connections to write data for these ...
Merge Join :Oracle performs a join between two sets of row data using the mergejoin algorithm. The inputs are two separate sets of row data. Output isthe results of the join. Oracle reads rows
Latest Answer: Merge Joins Sort merge joins can be used to join rows from two independent sources. Hash joins generally perform better than sort merge joins. On the other hand, sort merge joins can perform better than hash joins if both of the following conditions exist:The ...
Hash joing is implemented in CBO and comparatively faster. Merge joing is comparatively slow because both the row sources are to be sorted before merging.
Latest Answer: Hash join occupies lots of memory as it creates hashes ...
Choose - Choose either Rule based or Cost based depend on theavailability of statistics. If statistics is available on the table it usesCBO and if not it uses RBO. ALL_ROWS -
Latest Answer: The OPTIMIZER_MODE initialization parameter establishes the default behavior for choosing an optimization approach for the instance.CHOOSEThe optimizer chooses between a cost-based approach and a rule-based approach, depending on whether statistics are ...
Not sure about this, better we could try again with right samplesize in both the versions. Use DBMS_STATS.AUTO_SAMPLE_SIZE.ExecuteDBMS_STATS.GATHER_SCHEMA_STATS('SCOTT',estimate_percent=>DBMS_STATS.AUTO_SAMPLE_SIZE,GRANULARITY=>'ALL',CASCADE=>TRUE);
Latest Answer: Deafult Optimizer9i: CHOOSE10g: CBO ...
Cost is basically unit of work or resource used involved memory, I/Oand CPU to execute the query.Card( or Base cardinality) - is the number of rows in a base table captured by running statistics on the
SUBSTR returns a specified portion of a string eg SUBSTR('BCDEF',4) output BCDEINSTR provides character position in which a pattern is found in a string. eg INSTR('ABC-DC-F','-',2)
Latest Answer: hi Buddy, Substr only give the sub part of the stringSubstr(String,'start postion','length')Substr('ABCDEFAG',3,7); /*out put is =cdefag */Instr to give only possion of letter in use in a stringInstr(String,'letter',possition ...
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