30 Questions
Which of the following is not a primary data structure according to the text?
Table
In which decade did the Initial product releases of the example database systems occur?
1960s
What does the relational data structure organize data into?
Sets
Which data type is mentioned in the text as a part of the relational data structure?
Integer
What is a tuple according to the text?
A named tuple of values
Which database system is associated with 'Flexible schema' and 'Unstructured and semi-structured data'?
MongoDB
What are the relational operations based on set theory used to generate result tables from input tables?
Select, Project, Product, Join
Which SQL sublanguage is used for managing access to data in a relational database?
Data Control Language
What ensures the uniqueness of column names in a relational database?
Unique column names
What is the purpose of SQL constraints in a relational database?
To enforce business rules based on company policy
What statement is used to create a new database in SQL?
CREATE DATABASE
What are the components of a table in a relational database?
Name, sequence of columns, set of rows
What is the purpose of the SELECT statement in SQL?
To select rows from a table
What does the NOT NULL constraint do in SQL?
Prevents NULL values in a column
What is a primary key in SQL?
A column or group of columns used to uniquely identify a row
What does the TRUNCATE statement do in SQL?
Deletes all rows from a table
What is the purpose of a composite primary key in SQL?
To uniquely identify each row using multiple columns
What is the purpose of the WHERE clause in the SQL SELECT statement?
To specify conditions for selecting rows
What is an auto-increment column in MySQL?
A column that automatically receives a new value when a new row is added
What happens if a specific value is inserted into an auto-increment column in MySQL?
It overrides the auto-increment for a primary key
What is a foreign key in MySQL?
A column or group of columns that refers to a primary key
Under what circumstances can referential integrity violations occur in MySQL?
When a foreign key row is deleted
What does the ON DELETE clause of the FOREIGN KEY constraint specify in MySQL?
The action taken when a primary key row is deleted
What does the UNIQUE constraint ensure in MySQL?
It ensures unique values in a column or group of columns
Which SQL statement is used to delete an existing table and all its data?
DROP TABLE
Which data type is used for storing raw binary data in SQL?
BLOB
Which SQL statement is used to add, delete, or modify columns in an existing table?
ALTER TABLE
Which type of data is stored using the CHAR data type in SQL?
Fixed-length character strings
Which operator is used in SQL for unary negation?
NOT
Which SQL statement is used to select specific rows from tables based on various conditions?
SELECT
Study Notes
- The text discusses various SQL statements for managing tables and data in a database, including CREATE TABLE, DROP TABLE, and ALTER TABLE.
- CREATE TABLE statement creates a new table with specified name, column names, and data types.
- DROP TABLE statement deletes an existing table and all its data.
- ALTER TABLE statement modifies an existing table by adding, deleting, or modifying columns.
- Three common data types in relational databases: integer, decimal, and character.
- Integer data types include INT, SMALLINT, and others, with varying storage sizes and signed or unsigned ranges.
- Decimal data types include FLOAT and DECIMAL, with exact or approximate decimal values and different storage requirements.
- Character data types include CHAR and VARCHAR, with fixed or variable lengths and different storage requirements.
- Date and time data types include DATE, TIME, DATETIME, and TIMESTAMP, with different formats and ranges.
- Binary data types include BLOB and BINARY, for storing raw binary data.
- Spatial data types store geometric information, such as POINT, POLYGON, and GEOMETRY.
- Document data types include XML and JSON, for storing structured textual data.
- ALTER TABLE statement has three clauses for adding, modifying, or deleting columns, respectively.
- SQL supports various arithmetic, comparison, and logical operators for manipulating data.
- Operators can be unary or binary, and compute values from numeric, character, and other data types.
- Examples of arithmetic operators include addition (+), subtraction (-), multiplication (*), division (/), modulo (%), and exponentiation (^).
- Examples of comparison operators include equality (=), inequality (<>), greater than (>), less than (<), and range comparisons.
- Examples of logical operators include NOT (unary negation), AND, OR, and IN.
- SQL allows for selecting specific rows from tables based on various conditions with the SELECT statement.
Test your knowledge of SQL table statements with this quiz. Explore the concepts of creating, dropping, and altering tables, along with different data types for columns.
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