Which statement is true about database links?

• A.A public database link can be used by a user connected to the local database instance to connect to any schema in the remote database instance.
• B.Private database link creation requires the same user to exist in both the local and the remote databases.
• C.A database link can be created only between two Oracle databases.
• D.A public database link can be created only by sys.
• E.A database link created in a database allows a connection from that database's instance to the target database's Instance, but not vice versa.

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Examine the description of the PROMOTIONS table:

You want to display the unique promotion costs in each promotion category.
Which two queries can be used? (Choose two.)

• A.SELECT promo_cost, promo_category FROM promotions ORDER BY 1;
• B.SELECT DISTINCT promo_cost || ' in ' || DISTINCT promo_category FROM promotions ORDER BY 1;
• C.SELECT promo_category, DISTINCT promo_cost FROM promotions ORDER BY 2;
• D.SELECT DISTINCT promo_category || ' has ' || promo_cost AS COSTS FROM promotions ORDER BY 1;
• E.SELECT DISTINCT promo_category, promo_cost FROM promotions ORDER BY 1;

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Which two statements are true about UNDO and REDO? (Choose two.)

• A.DML modifies Oracle database objects and only generates REDO
• B.The generation of UNDO generates REDO
• C.DML modifies Oracle database objects and only generates UNDO
• D.The generation of REDO generates UNDO

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Which three statements are true concerning logical and physical database structures? (Choose three.)

• A.A segment might have only one extent
• B.A segment's blocks can be of different sizes
• C.All tablespaces may have one or more data files
• D.Segments can span multiple tablespsaces
• E.The extents of a segment must always reside in the same datafile
• F.A segment can span multiple data files in some tablespaces
• G.A smallfile tablespace might be bigger than a bigfile tablespace

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You want to write a query that prompts for two column names and the WHERE condition each time it is executed in a session but only prompts for the table name the first time it is executed.
The variables used in your query are never undefined in your session.
Which query can be used?

• A.SELECT &col1, &col2FROM "&table"WHERE &condition;
• B.SELECT &&col1, &&col2FROM &tableWHERE &&condition = &&cond;
• C.SELECT &&col1, &&col2FROM &tableWHERE &&condition;
• D.SELECT '&&col1', '&&col2'FROM &tableWHERE '&&condition' = '&cond';
• E.SELECT &col1, &col2FROM &&tableWHERE &condition;

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