Shared SQL Dependency Management (249)

In addition to managing dependencies among schema objects, Oracle also manages
dependencies of each shared SQL area in the shared pool. If a table, view, synonym, or
sequence is created, altered, or dropped, or a procedure or package specification is
recompiled, all dependent shared SQL areas are invalidated. At a subsequent
execution of the cursor that corresponds to an invalidated shared SQL area, Oracle
reparses the SQL statement to regenerate the shared SQL area.

共享SQL的依賴性管理
1. Oracle不僅管理方案物件之間的依賴性，還需管理共享池中各個共享 SQL 區的依賴性
2. 使用者建立，修改或移除了表，索引，同義詞，或序列，或者重新編譯了包，或包宣告，那麼所有依賴共享 SQL 區都將被置為無效
3. 當一個基於無效共享 SQL 區的遊標繼續執行時，Oracle 將重新對 SQL 語句進行語法分析，並 重新生成共享 SQL 區

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