Question

Fill in the blanks in cach of the following statements: a) The international standard database language is __________. b) \(A\) table in a database consists of _________ amd __________. c) Statement objects return SQL query results as __________ objects. d) The _________ uniquely identifies each row in a table. e) SQL keyword _________ is followed by the selection criteria that specify the rows to select in a query. f) SQL keywords _________ specify the order in which rows are sorted in a query. g) Merging rows from multiple database tables is called _________ the tables. h) \(A(n)\)_________ is an organized collection of data. i) \(A(n)\) _________ is a set of columns whose values match the primary key values of another table. j) \(A(n)\) _________object is used to obtain a Connection to a database. k) Interface _________ helps manage the connection between a Java program and a database. l) \(A(n) \quad\)_________ object is used to submit a query to a database. m) Unlike a Resultset object, _________ and _________ objects are scrollable and updatable by default. n) _________ a disconnected RowSet, caches the data of a Resul tset in memory.

Short answer

a) SQL b) Rows and Columns c) ResultSet d) Primary Key e) WHERE f) ORDER BY g) Joining h) Database i) Foreign Key j) DriverManager k) JDBC l) Statement m) RowSet and CachedRowSet n) CachedRowSet

Step-by-step solution

Answer a

The international standard database language is often used for managing and manipulating relational databases. The language referred to here is SQL.

Answer b

In a relational database, a table is constructed of rows and columns. These are essential components of the table structure.

Answer c

In JDBC (Java Database Connectivity), Statement objects execute SQL statements and return their results as ResultSet objects.

Answer d

The primary key uniquely identifies each row in a table, ensuring that each row can be correctly identified.

Answer e

In SQL, the keyword WHERE is followed by selection criteria to specify which rows should be selected in a query.

Answer f

In SQL, the keywords ORDER BY are used to specify the order in which rows are sorted in the result of a query.

Answer g

The process of combining rows from multiple tables in a relational database is called joining the tables.

Answer h

A database is an organized collection of data, typically stored and accessed electronically from a computer system.

Answer i

A foreign key is a set of columns in one table that refers to the primary key in another table.

Answer j

In JDBC, a DriverManager object is used to obtain a Connection to a database.

Answer k

The interface that helps manage the connection between a Java program and a database is the JDBC API.

Answer l

In JDBC, a Statement object is used to submit a query to a database.

Answer m

In JDBC, RowSet and CachedRowSet objects are scrollable and updatable by default, in contrast to ResultSet objects.

Answer n

A CachedRowSet is a disconnected RowSet that caches the data of a ResultSet in memory.

Key concepts

SQL language

Structured Query Language, commonly known as SQL, is the standard language used to communicate with relational databases. It provides a way to perform a variety of operations such as querying data, updating records, and managing database structures. SQL is vital because it allows users to:

• Retrieve data from a database using the SELECT statement
• Insert new data into a database with the INSERT statement
• Modify existing data through the UPDATE command
• Remove unwanted data by using the DELETE statement

These commands, alongside others like WHERE and ORDER BY, enable precise data manipulation and control within databases.

Database tables

A database table is an essential structure in a relational database, consisting of rows and columns. Each column in a table corresponds to a specific attribute or field of the data, whereas each row represents a single record entry. Tables are linked through keys:

• Primary Key: A unique identifier for each row, making it distinct.
• Foreign Key: A column or a set of columns in one table that references the primary key of another table, establishing a relationship between tables.

Ensuring each table maintains its integrity and correctly references others is crucial to a well-structured database.

JDBC API

Java Database Connectivity (JDBC) API is a vital component that facilitates the interaction between Java applications and databases. By using JDBC, developers can execute SQL statements, retrieve and update data, and manage other database-related tasks within a Java program. Key components of JDBC include:

• DriverManager: Responsible for managing a list of database drivers and connecting an application to a database.
• Connection: Represents a session with a specific database.
• Statement: An object used to execute SQL queries against the database.

Through JDBC, Java applications can seamlessly incorporate database functionalities.

ResultSet and RowSet objects

In the context of JDBC, ResultSet and RowSet are crucial objects that hold data retrieved from databases:

• ResultSet: A JDBC object which holds data obtained from executing SQL queries. It is typically non-scrollable and read-only by default.
• RowSet: Enhanced versions of ResultSet objects. They are scrollable and updatable, with the capability to perform operations even when disconnected from the database.
• CachedRowSet: A type of RowSet that can store data retrieved from a ResultSet in memory, maintaining data even when the database connection is closed.

These objects provide Java applications with versatile options for handling and manipulating SQL query results effectively.