# SQLiteDatabase for beginners quiz answers These are the answers for the Quizzes in the `SQLiteDatabase for Beginners` Lesson. Correct answers are marked in **bold**. ## Quiz answers ### Quiz 1: Available SQLite classes Use this Quiz to check what you have learned. Some questions may have more than one right answer. Question 1.1: SQLiteDatabase is available for all the supported platforms. - **Yes**. - No. Question 1.2: What are the platforms supported by SQLiteDatabase? - Desktop, Web - Web, Console, Mobile (iOS & Android). - Desktop, Web, Mobile (iOS & Android) - Desktop, Console, Web - **Desktop, Web, Mobile (iOS & Android), Console** Question 1.3: SQLite can be used only in single user mode. - **No**. - Yes. Question 1.4: SQLite works in 32-bit mode even when the app is deployed as 64-bit. - True. - **False**. ### Quiz 2: In-memory SQLite databases Use this Quiz to check what you have learned. Some questions may have more than one right answer. Question 2.1: A Xojo app only can use one in-memory database at once. - Yes. - **No**. Question 2.2: Sort the following lines of code to create an in-memory database - dbsource = New SQLiteDatabase - If Not dbsource.Connect Then - MessageBox("Error Creating the Database") - Exit - End If Question 2.3: We only can create in-memory databases that are going to use less than 2 GB of RAM - True. - **False**. Question 2.4: Once a table has been created, we can… - Delete columns. - Modify some of the current columns. - **Add new columns to the table**. Question 2.5: Once we create a SQLite database instance and assign it to a variable we can start using it. - Yes. - No. - **Yes, always the variable or property is in scope during database use.** Question 2.6: We still can use a in-memory database the next time we run the app. - Yes, always it has valid data - **No, the database is deleted once we exit the app.** Question 2.7: Once we create an SQLiteDatabase we just need to use the Connect method to start using it. - Yes. - No. - **Yes, always the Connect method has returned True as result.** ### Quiz 3: tables Use this Quiz to check what you have learned. Some questions may have more than one right answer. Question 3.1: SQLite sets a maximum number of tables for a database. - **No**. - Yes. Question 3.2: In order to create a table in Xojo we will use the SQLSelect method from the SQLiteDatabase or iOSSQLiteDatabase classes. - True. - **False**. Question 3.3: After creating a Table using SQLExecute we will get the result of the operation as a Boolean value. - True. - **False**. Question 3.4: Once a Table has been created, it is possible to modify the name of any of the defined columns - **True.** - False. Question 3.5: Once a Table has been created, it is possible to deleted any of its columns. - True. - **False**. ### Quiz 4: DatabaseRecord Use this Quiz to check what you have learned. Notice that the questions may have more than one right answer. Question 4.1: The name of the Class to add new records to the database is… - SQLiteRecord. - DatabaseField. - Record. - **DatabaseRecord**. Question 4.2: We have to observe the correct use of lowercase and uppercase letters in the name when referring the database columns. - Yes. - **No, it doesn't matter when using SQLite**. Question 4.3: The method name of the SQLiteDatabase and iOSSQLiteDatabase classes to add new records is… - AddRecord. - InsertField. - AddDatabaseRecord. - **InsertRecord**. Question 4.4: We can add new records using a SQL statement executed with SQLSelect on the database instance. - True. - **False**. Question 4.5: Sort the lines to add a record using the DatabaseRecord Class. - Var nr As New DatabaseRecord - nr.Column("nombre") = "Nombre " + n.ToString - dbsource.InsertRecord("prueba", nr) ### Quiz 5: retrieving records Use this Quiz to check what you have learned. Some questions may have more than one right answer. Question 5.1: The name of the class we use to navigate and access the records from a database query is… - DatabaseRecord. - DataGroup. - Records. - RecordList. - **RecordSet**. Question 5.2: We can iterate the records from a RecordSet as many times as we need. - Yes. - No. - **Yes, always move the cursor pointer to the first record in first place.** Question 5.3: Once we get a RecordSet we can access to it from any point of our app. - Yes. - No. - **It depends if the variable or property that references the RowSet is in scope.** Question 5.4: We just need to test the RecordSet for Nil in order to start using it - True. - Not always. - **We also need to make sure that AfterLastRow is False, for example.** Question 5.5: RecordSet offers methods to Delete, Edit and Insert records among other operations. - Yes. - No. - **Only Delete and Edit, among other actions.** Question 5.6: What are the method names we have to use to navigate the RecordSet? - **MoveFirst, MoveNext, MovePrevious, MoveLast.** - JumpFirst, Next, Rewind, JumpLast. - MoveFirst, Next, Previous, MoveLast. - MoveNext, MovePrevious Question 5.7: The method we use to know the number of records in a RecordSet is… - **RecordCount**. - Records. - NumberOfRecords. - TotalRecords Question 5.8: A RecordSet is closed when… - **We call the Close method on the instance.** - **The instance gets out of Scope.** - **The App quits.** - A RecordSet never closes, it's always available. - We get an Error. ### Quiz 6: editing records Use this Quiz to check what you have learned. Some questions may have more than one right answer Question 6.1: What method should we use to access a column value from a record? - Value. - Record. - DataField. - **Field**. Question 6.2: Can we directly access a column value using the Field method? - Yes, sure. - No, we have to query the database using SQLSelect. - No, we have to use a DataRecord instance. - **No, we do it using a DatabaseField instance.** Question 6.3: What RecordSet method should we call before we can modify a record data? - Prepare. - Rollback. - DataEdit. - **Edit**. Question 6.4: What's the main advantage of using SQLExecute instead of RecordSet when updating a record? - None, in fact it is preferable and easier to use RecordSet. - SQLExecute provides greater flexibility. - **SQLExecute provides greater flexibility and returns a new RecordSet with the data already updated.** ### Quiz 7: file-based SQLite databases Use this Quiz to check what you have learned. Some questions may have more than one right answer. Question 7.1: Sort the lines of code to create a file based SQLite database - DBSourceDisk = New SQLiteDatabase. - Var file As FolderItem = SpecialFolder.Documents.Child("tet.sqlite") - If file \<\> Nil Then - DBSourceDisk.DatabaseFile = file. - Try - DBSourceDisk.CreateDatabase - Catch error As IOException - MessageBox("Error Creating the Database".) - End Ty - Else - MessageBox("Error Found while Creating the File") - End If Question 7.2: What's the effect when calling the 'CreateDatabase' on a file that already has SQLite data on it? - It will delete the current contents, initializing again the file in order to be used by the SQLite database instance. - The app will raise an Exception. - The app will create a copy of the file, initializing it so it can be used by the SQLite database instance. - **It will act as if the method 'Connect' was called.** Question 7.3: SQLite creates the database file encrypted by default. - True. - **False**. - It's true, but using a 128 bits length. Question 7.4: What SQL statement we will use to delete all the records from a Table? - **DELETE FROM table_name.** - DELETE \* FROM table_name. - DELETE all FROM table_name. - DELETE FROM table_name WHERE id = \*. - DROP TABLE table_name. Question 7.5: Can we change the file used by a SQLite database instance on the fly? - Yes. - **No**. ### Quiz 8: backup Use this Quiz to check what you have learned. Notice that the questions may have more than one right answer. Question 8.1: We only can backup in-memory databases - Yes. - **No**. Question 8.2: The backup is done over… - A valid FolderItem instance that is in scope during all the process. - Another in-memory or file based database. - **Another file based and initialized SQLite database.** Question 8.3: What modes can we use to backup a SQLite database? - Synchronous and Asynchronous modes. - Synchronous, Direct and Muliuser modes. - **Synchronous and Asynchronous modes.** Question 8.4: What measure of time should we use to set the period in a Synchronous backup? - Seconds. - Microseconds. - Milliseconds. - **We have to pass -1 as the value for the parameter.** Question 8.5: Once the backup has finished, the SQLite database instance will use the file of the target database. - True. - **False**. ### Quiz 9: asynchronous backup Use this Quiz to check what you have learned. Some questions may have more than one right answer. Question 9.1: Why is it preferable to use asynchronous backups instead of synchronous? - **The app is not blocked.** - It only works with big database files. - **It provides more control, for example the ability to cancel the backup process.** - **We can receive information about the process progress and possible errors.** Question 9.2: What is the name of the Class Interface that we have to implement in the class used as backup handle? - **SQLiteBackupInterface**. - SQLiteBackupProgress. - SQLiteBackupInformation. Question 9.3: Do we have to implement (add code) in all the methods added by the SQLiteBackupInterface? - **Yes**. - No. Question 9.4: The object used as backup handle, has to be in scope during all the process? - **Yes**. - No. - Only if we had implement code on any of the Class Interface methods. Question 9.5: It's mandatory to pass the time period parameter to the Backup method? - **No**. - Yes. ### Quiz 10: ciphering SQLite databases Use this Quiz to check what you have learned. Some questions may have more than one right answer. Question 10.1: Xojo uses by default a ciphering length of 256 bits? - Yes. - **No**. Question 10.2: What prefix string should we use in the password to enable the 256 bits ciphering length? - **aes256:** - 256: - [aes256]() - maxSecure: Question 10.3: What method should we use in order to encrypt an already existing SQLite database file? - **Encrypt**. - EncryptionKey. - CipherDB. - Encrypt(""). Question 10.4: How can we decrypt an already ciphered database once we are connected to it? - **Encrypt("").** - **Decrypt**. - Wipe. - EncryptionKey = "".