language, transaction-control, backup-restore, utility, or non-preparable statements. Subtasks --- UPDATE and DELETE statements have two syntax forms: single- and multi-table. Multiple-table statement implementation deals with a top-level JOIN structure like SELECT statements do, so the same approa...
#1Explain how ODBC, OLE DB, and ADO are related and the difference in what they offer. #2. What role does the DBMS driver serve? Who supplies it? #3. What are BI systems? #4. How do BI systems differ from transaction processing system...
Oracle Database generates an internal SQL statement, which in turn generates a recursive call. In short, recursive calls are basically SQL performed on behalf of your SQL. So, if you had to parse the query, for example, you might have had to run some other queries to get ...
It would be more efficient to drive from the TRANSACTION table because there are no limiting conditions on the customer table. The database would join rows from the TRANSACTION table to the ACCOUNT table, and finally to the CUSTOMER table. In this case, the indexes used on the ACCOUNT and ...
This means for a given SQL or DML statement the execution plan that was used for the last execution will be shown. The following matrix shows what type of execution plan you can see in which transaction for the different databases: Database (SAP name) ST05 ST04 DB2 estimated execution ...
SQL>SELECT plan_table_output FROM TABLE(DBMS_XPLAN.DISPLAY('PLAN_TABLE')); 示例: SQL>EXPLAIN PLAN FOR SELECT * FROM DAVE; 已解释。 SQL>SELECT plan_table_output FROM TABLE(DBMS_XPLAN.DISPLAY('PLAN_TABLE')); 或者: SQL>select * from table(dbms_xplan.display); ...
A transaction may be in the middle of some operation; the DBMS must ensure the atomicity of the transaction in this case. It should check whether the transaction can be completed now or it needs to be rolled back. No transactions would be allowed to leave the DBMS in an inconsistent state...
PARTITIONSSpecifies to display the partition-related information. FORMAT = {TRADITIONAL| JSON}The output format ofEXPLAIN. Valid values: TRADITIONAL: presents the output in the tabular format. JSON: presents the output in theKEY:VALUEformat. The output is displayed as JSON strings, includingEXTENDED...