Databases Handling MCQs with Explanations

The updated MySQL extension with PHP 5 is known as MySQL and typically referred to as mysqli.

Also make sure that extension_dir directive points to the appropriate directory.

PHP required that MySQL client library be installed on the server from which PHP was communicating with MySQL, whether the MySQL server also happened to reside locally or elsewhere. PHP 5.3 removes this problem by introducing MySQL Native Driver.

If you choose to interact with MySQL server using the object-oriented interface, you need to first instantiate the mysqli class via its constructor.

The mysqli extension includes a few features that can be used to capture error messages or alternatively you can use exceptions.

Error numbers are often used in lieu of natural-language message to ease software internationalization efforts and allow for customization of error messages.

An example of this-

Its prototype looks like- class mysqli { mixed query(string query [, int resultmode]) }

Once this method is executed, the result set is no longer available.

Their prototype is as follows- calss mysqli_result { mixed fetch_array ([int resulttype]) } calss mysqli_result { mixed fetch_row() }

The method num_rows() is only useful for determining the number of rows retrieved by a SELECT query. But to retrieve the number of rows affected by INSERT, UPDATE, or DELETE query, use affected_rows().

When the query() method is looped repeatedly it comes at a cost of both overhead, because of the need to repeatedly parsing of the almost identical query for validity, and coding convenience, because of the need to repeatedly reconfigure the query using the new values for each iteration. To help resolve the issues incurred by repeatedly executed queries, MySQL introduced prepared statements.

Once the statement has been prepared, it needs to be executed. Exactly when it’s executed depends upon whether you want to work with bound parameters or bound results. In the case of bound parameters, you’d execute the statement after the parameters have been bound with the bind_param() method.

Once you’ve finished using a prepared statement, the resources it requires can be recuperated with the close() method.

Its prototype follows: class mysqli { boolean fetch() }

Its prototype follows: class mysqli { boolean rollback() }

Your function should look like this: function adminLinks($page, $url) { //Build admin links here }

You place your administrative links only on the full display of an entry, so you must place the call to load information from adminLinks() within a conditional statement

You need to modify .htaccess with an additional rule that handles URLs passed in a link to admin.php.

The vertical pipe character (|) is the regular expression equivalent of “or”.

([w-]+), will match one or more word characters and/or hyphens—which is what your custom entry URLs consist.

If an entry is being edited, you need to load the existing entry data and save each piece in a variable.

In admin.php, you check whether $_GET[‘page’] == ‘delete’, then pass the entry URL to be deleted to a function.

To process this, you need to add an additional block of code to the top of admin.php that determines what choices you’ve made and act accordingly.

If the function is successful, you send the user to the main page. If it fails, you stop execution of the script and display an error, letting the user know that something went wrong.

MySQL is the correct answer to “Which one of the following databases has PHP supported almost since the beginning”. This question is standard in competitive examination syllabi for Databases Handling.

CREATE TABLE table_name (column_name column_type) is the correct answer to “Which one of the following statements is used to create a table”. This question is standard in competitive examination syllabi for Databases Handling.

$mysqli->select_db(‘databasename’) is the correct answer to “Which one of the following statements can be used to select the database”. This question is standard in competitive examination syllabi for Databases Handling.

Empty String is the correct answer to “If there is no error, then what will the error() method return”. This question is standard in competitive examination syllabi for Databases Handling.

None of the above is the correct answer to “Which of the following DBMSs do not have a native PHP extension”. This question is standard in competitive examination syllabi for Databases Handling.

mysql_connect() function is the correct answer to “In PHP in order to access MySQL database you will use:”. This question is standard in competitive examination syllabi for Databases Handling.

True is the correct answer to “Transactions are used to treat sets of SQL statements atomically.”. This question is standard in competitive examination syllabi for Databases Handling.

True is the correct answer to “SQL is not case sensitive. SELECT is the same as select.”. This question is standard in competitive examination syllabi for Databases Handling.

CURRENT_DATE() is the correct answer to “Which of the following is not an SQL aggregate function”. This question is standard in competitive examination syllabi for Databases Handling.

It causes rows with the same ID to be sorted by NAME in descending order is the correct answer to “What does the DESC keyword do in the following query? SELECT * FROM MY_TABLE WHERE ID > 0 ORDER BY ID, NAME DESC"”. This question is standard in competitive examination syllabi for Databases Handling.

DROP TABLE is the correct answer to “The ............. statement is used to delete a table.”. This question is standard in competitive examination syllabi for Databases Handling.

The database will remain unchanged is the correct answer to “What will happen at the end of the following sequence of SQL commands? BEGIN TRANSACTION DELETE FROM MYTABLE WHERE ID=1 DELETE FROM OTHERTABLE ROLLBACK TRANSACTION”. This question is standard in competitive examination syllabi for Databases Handling.

TRUNCATE TABLE is the correct answer to “Use the .............. to delete the data inside the table, and not the table itself”. This question is standard in competitive examination syllabi for Databases Handling.

True is the correct answer to “Can joins be nested”. This question is standard in competitive examination syllabi for Databases Handling.