oracle pl sql interview questions

1. Tell some new features in PL/SQL in 10g (Intermediate to Advanced)
- Regular expression functions REGEXP_LIKE , REGEXP_INSTR, REGEXP_REPLACE, and REGEXP_SUBSTR
- Compile time warnings
- Conditional compilation
- Improvement to native compilation
- BINARY_INTEGER made similar to PLS_INTEGER
- INDICES OF , VALUES OF in FORALL lets you work on non-consecutive indices
- Quoting mechanism . Instead of quoting single quotes twice everytime, give your own delimiter to go on using single quotes.
Ex: q'!I'm a string, you're a string.!'
- Flashback Query functions. SCN_TO_TIMESTAMP, TIMESTAMP_TO_SCN
- Implicit conversion between CLOB and NCLOB
- Improved Overloading
- New datatypes BINARY_FLOAT, BINARY_DOUBLE
- Global optimization enabled
- PLS_INTEGER range increased to 32bit
- DYNAMIC WRAP using DBMS_DDL

2. What is a sequence ?
- A database object that offers high-speed access to an integer value
- Guaranteed to be unique (within that sequence).
-Used commonly to generate Primary key values

3. What is MERGE ?
Combination of INSERT and UPDATE

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