JDBC Flashcards
What is a database?
An organized collection of data.
A database management system (DBMS) provides mechanisms for storing, organizing, retrieving, and modifying data.
What does DBMS stand for?
Database Management System
What is SQL?
Structured Query Language, the international standard language used with relational databases to perform queries and manipulate data.
How is ‘SQL’ pronounced?
Either ‘sequel’ or as its individual letters.
What is JDBC?
Java Database Connectivity, an API for Java programs to interact with databases.
What is the purpose of a JDBC driver?
To enable Java applications to connect to a specific database in a DBMS.
What is a relational database?
A logical representation of data that allows access without consideration of its physical structure, storing data in tables.
What are SQL queries used for?
To specify which subsets of data to select from a table.
What is the primary key in a database?
Uniquely identifies each row/record in a database table.
What does the NOT NULL constraint do?
Ensures that a column cannot have a NULL value.
What is the purpose of database normalization?
To efficiently organize data in a database by eliminating redundant data and ensuring data dependencies make sense.
What are the main types of SQL commands?
- DDL - Data Definition Language
- DML - Data Manipulation Language
- DCL - Data Control Language
Fill in the blank: A _______ is used to create and retrieve data from the database very quickly.
INDEX
What is the purpose of the WHERE clause in SQL?
To specify selection criteria for a query.
What do the wildcard characters ‘%’ and ‘_’ represent in SQL?
- ’%’ - zero or more characters
- ‘_’ - a single wildcard character
What does the ORDER BY clause do?
Sorts the rows in the result of a query into ascending or descending order.
What is an INNER JOIN?
A SQL operation that merges rows from two tables by matching values in columns common to both tables.
What is the role of the ON clause in an INNER JOIN?
Specifies the columns compared to determine which rows are merged.
What is the default value constraint?
Provides a default value for a column when none is specified.
What is a CHECK constraint?
Ensures that all values in a column(s) satisfy certain conditions.
What does the UNIQUE constraint ensure?
That all the values in a column are different.
What is the significance of the ‘Authors’ table in the books database?
It stores information about authors including FirstName and LastName.
What does the ‘Titles’ table store?
Information about book titles including ISBN, Title, EditionNumber, and Copyright.
What is the relationship between authors and titles in the books database?
Stored in the AuthorISBN table, which links authors to their corresponding titles.
What is the purpose of using a primary key in a table?
To uniquely identify each record in the table.
Fill in the blank: The _______ constraint limits the type of data that can go into a table.
Constraints
What is the first normal form (1NF) in database normalization?
A stage of normalization that ensures the table is organized in a way that eliminates duplicate data.
True or False: The SQL command ‘INSERT INTO’ is used to add new records to a database.
True
What is a foreign key?
A column that uniquely identifies a row/record in another database table.
What is the purpose of a qualified name in SQL?
To specify the columns from each table that should be compared to join the tables.
The syntax is used when columns have the same name in both tables.
What is the basic form of an INSERT statement?
INSERT INTO tableName (column1, column2, …) VALUES (value1, value2, …)
The list of column names is not required if a value for every column is specified in the correct order.
What does an UPDATE statement do?
Modifies data in a table.
The basic form is UPDATE tableName SET columnName = value.
What is the purpose of a DELETE statement in SQL?
Removes rows from a table.
The optional WHERE clause specifies which rows to delete.
What is MySQL Connector/J?
A JDBC driver for MySQL databases distributed as a .zip or .tar.gz archive.
It includes the JAR archive named mysql-connector-java-version-bin.jar.
What does JDBC support in terms of driver discovery?
Automatic driver discovery.
It loads the database driver into memory automatically.
What method is used to connect to a database using JDBC?
DriverManager.getConnection()
It takes the database URL, username, and password as arguments.
What is the function of the Statement object in JDBC?
To submit SQL statements to the database.
It is obtained using the createStatement() method of the Connection object.
What does the executeQuery method of the Statement object do?
Submits a query and returns a ResultSet containing the query results.
What is a ResultSet in JDBC?
An object that contains the results of a SQL query.
It provides methods to manipulate the query result.
What is the purpose of the ResultSetTableModel class?
To provide a TableModel for displaying query results in a JTable.
What class is used to sort rows in a JTable?
TableRowSorter
It interacts with the underlying TableModel to reorder rows based on column data.
What does filtering rows in a JTable refer to?
Showing subsets of the data from the underlying TableModel.
What are the two types of RowSet objects?
- Connected RowSet
- Disconnected RowSet
What is a JdbcRowSet?
A connected RowSet that acts as a wrapper around a ResultSet object.
What is a CachedRowSet?
A disconnected RowSet that caches data from a ResultSet in memory.
It is scrollable and updatable by default.
What is the role of PreparedStatement in JDBC?
To create compiled SQL statements that execute more efficiently and allow parameter specification.
What do the question marks (?) in a PreparedStatement represent?
Placeholders for values that will be passed as part of the query.
What is the function of the CallableStatement interface?
To invoke stored procedures in a database.
What is a stored procedure?
A named collection of SQL statements stored in a database.
