Performing operations on cursors in PostgreSQL - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a cursor named my_cursor for selecting all rows from the employees table.

PostgreSQL

DECLARE my_cursor CURSOR FOR SELECT * FROM [1];

Drag options to blanks, or click blank then click option'

Aemployees

Bdepartments

Csalaries

Dprojects

Attempts:

3 left

💡 Hint

Common Mistakes

Using a table name that does not exist.

Forgetting to specify the table after SELECT * FROM.

The cursor is declared to select all rows from the employees table.

2fill in blank

medium

Complete the code to open the cursor named my_cursor.

PostgreSQL

[1] my_cursor;

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ACLOSE

BFETCH

COPEN

DDECLARE

Attempts:

3 left

💡 Hint

Common Mistakes

Using FETCH instead of OPEN to start the cursor.

Trying to DECLARE the cursor again instead of opening it.

The OPEN statement is used to start the cursor so it can be used to fetch rows.

3fill in blank

hard

Fix the error in the code to fetch one row from the cursor my_cursor into the variable emp_record.

PostgreSQL

FETCH [1] my_cursor INTO emp_record;

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ANEXT

BALL

CPRIOR

DFIRST

Attempts:

3 left

💡 Hint

Common Mistakes

Using ALL fetches all rows, which is not valid syntax here.

Using PRIOR or FIRST fetches rows in different directions, which may cause errors.

The NEXT option fetches the next row from the cursor, which is the default and correct choice here.

4fill in blank

hard

Fill both blanks to close the cursor and then deallocate it.

PostgreSQL

[1] my_cursor;
[2] my_cursor;

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ACLOSE

BOPEN

CDEALLOCATE

DFETCH

Attempts:

3 left

💡 Hint

Common Mistakes

Trying to deallocate before closing the cursor.

Using OPEN or FETCH instead of CLOSE or DEALLOCATE.

First, the cursor is CLOSEd to stop it, then DEALLOCATEd to free resources.

5fill in blank

hard

Fill all three blanks to declare a cursor named emp_cursor for employees with salary over 50000, open it, and fetch one row into emp_rec.

PostgreSQL

DECLARE [1] CURSOR FOR SELECT * FROM employees WHERE salary [2] 50000;
[3] [1];
FETCH NEXT [1] INTO emp_rec;

Drag options to blanks, or click blank then click option'

Aemp_cursor

B>

COPEN

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong cursor name or inconsistent names.

Using < or other operators instead of > for salary condition.

Forgetting to open the cursor before fetching.

The cursor is named emp_cursor. It selects employees with salary greater than 50000. Then it is OPENed before fetching.