Slajd PPT
Objaśnianie planu wykonania polecenia SQL
SQL> GRANT PLUSTRACE TO SCOTT
SQL> SET AUTOTRACE TRACEONLY EXPLAIN
SQL> select nazwisko from pracownicy where id_prac=100;
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0 SELECT STATEMENT Optimizer=CHOOSE (Cost=1 Card=1 Bytes=22)
1 0 TABLE ACCESS (BY ROWID) OF 'PRACOWNICY' (Cost=1 Card=1 Bytes=22)
2 1 INDEX (UNIQUE SCAN) OF 'PK_PRAC' (UNIQUE)