CREATE TABLE books(id INTEGER PRIMARY KEY,name TEXT.,rating INTEGER);. INSERT INTO books VALUES (1, "Carrie", 3);. INSERT INTO books. Read and learn for free about the following scratchpad: Challenge: Book list database. I was wondering if there is an online book database? If I look up an Note that there is a lot of crossover between their worst books list as well.
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ISBNdb is one of the most comprehensive book databases on the web. Using data from hundreds of libraries, publishers, merchants and other sources around . Books shelved as database: Seven Databases in Seven Weeks: A Guide to Modern Databases and the NoSQL Movement by Eric Redmond, SQL and. This free book database will change your life. Find out how Within seconds, you've got a list of books similar to the one you've searched for.
The second part of the rule says that a table cannot have two columns containing the same information. For example, the following possible redesign of the book table provides a solution to the previous problem by having a separate column for each author of the book.
However, the table has two duplicative columns: author1 and author2.
These two columns both record the same information, author names, so this design also violates first normal form. A possible redesign that satisfies the requirement that each column is atomic and not duplicative is shown below.
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We now have just one column for the book title and one column for the names of the authors. Notice that the second book now occupies two rows because it has two authors. In other words, every table must have a primary key. Can we find a primary key in the table above? Neither the title column nor the author column by itself is any use as a primary key because some values repeat in each of these columns.
We could combine the two columns to create a composite primary key.
However, it is also important to think about not just the data that are currently in a table, but also what possible values could be entered into the table in the future or even just in theory. In this case, it is possible that a book could be published in both hard cover and paperback formats, both of which would have the same title and author, so while a composite primary key would work for the three rows shown below, it is not necessarily a smart choice.
As described previously, for the case of information about books, a great candidate for a primary key is the book's ISBN because it is guaranteed to be unique for a particular book. If we add an ISBN column to the table, we can finally satisfy first normal form, though it still has to be a composite primary key involving the combination of ISBN and author.
Consideration of second and third normal form will help to improve the design. Second normal form Second normal form requires that a table must be in first normal form and all columns in the table must relate to the entire primary key. This rule formalizes the idea that there should be a table for each entity in the data set. As a very basic example, consider the following table that contains information about authors and publishers.
The primary key of this table is the author ID. In other words, each row of this table only concerns a single author.
However, the publisher column does not relate to the primary key. This is the publisher of a book. In other words, the information about publishers belongs in a table about publishers or possibly a table about books , not in a table about authors.
As a more subtle example, consider the table that we ended up with at the end of first normal form. The title column relates to the ISBN; this is the title of the book.
However, the title column does not relate to the author; this is not the title of the author! The table needs to be split into two tables, one with the information about books and one with the information about authors. Shown below is the book-related information separated into its own table.
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In this case, it would be wise to add an ID column to act as the primary key for the table of authors, as shown below, because it is entirely possible that two distinct authors could share the same name. In this case, the relationship is many-to-many, so the solution requires a third table to provide a link between books and authors. ID] ID book author -- 2 2 6 2 7 5 Third normal form Third normal form requires that a table must be in second normal form and all columns in the table must relate only to the primary key not to each other.
This rule further emphasizes the idea that there should be a separate table for each entity in the data set.
For example, consider the following table for storing information about books. The title column relates to the book; this is the title of the book. Each row of this table is about one book. The publisher column also relates to the book; this is the publisher of the book. However, the country column does not relate directly to the book; this is the country of the publisher.
That obviously is information about the book--it is the country of the publisher of the book--but the relationship is indirect, through the publisher. There is a simple heuristic that makes it easy to spot this sort of problem in a database table.
Notice that the information in the publisher and country columns is identical for the books published by Mallinson Rendel. When two or more columns repeat the same information over and over, it is a sure sign that either second or third normal form is not being met. In this case, the analysis of the table suggests that there should be a separate table for information about the publisher. Applying the rules of normalization usually results in the creation of multiple tables in a database.
The previous discussion of relationships should be consulted for making sure that any new tables are linked to at least one other table in the database using a foreign-key, primary-key pair.
However, normalization may produce a database that is slow in terms of accessing the data because the data from many tables has to be recombined.
Denormalization is the process of deliberately violating normal forms, typically in order to produce a database that can be accessed more rapidly. Less repetition also means that a well-designed database is easier to maintain and update, because if a change needs to be made, it only needs to be made in one location. Furthermore, there is less chance of errors creeping into the data set. If there are multiple copies of information, then it is possible for the copies to disagree, but with only one copy there can be no disagreements.
These ideas are an expression of the DRY principle from Section 2. A well-designed database is the ultimate embodiment of the DRY principle for data storage.
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The data were originally stored as plain text files, where each file contains the data for one variable for one month. As we have discussed earlier in this chapter, this simple format makes the data very accessible.
However, this is an example where a plain text format is quite inefficient, because many values are repeated. For example, the longitude and latitude information for each location in the data set is stored in every single file, which means that that information is repeated over times!
That not only takes up more storage space than is necessary, but it also violates the DRY principle, with all of the negative consequences that follow from that. The file contains information on latitude and longitude that is repeated in every other plain text file in the original format for each variable and for each month; in total, over times. In this section, we will consider how the Data Expo data set could be stored as a relational database. To start with, we will consider the problem from an entities and attributes perspective.
What entities are there in the data set? In this case, the different entities that are being measured are relatively easy to identify.
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There are measurements on the atmosphere, and the measurements are taken at different locations and at different times. We have information about each time point i. This suggests that we should have three tables: one for atmospheric measures, one for locations, and one for time points. It is also useful to look at the data set from a normalization perspective.
For this purpose, we will start with all of the information in a single table only 7 rows shown : date lon lat elv chi cmid clo ozone press stemp temp Moving on to second normal form, the column elv elevation immediately fails.
The elevation at a particular location clearly relates to the longitude and latitude of the location, but it has very little to do with the date.
We need a new table to hold the longitude, latitude, and elevation data. The new table design and the first three rows of data are shown below.
It has a primary key a combination of longitude and latitude , and the elv column relates directly to the entire primary key. Going back to the original table, the remaining columns of atmospheric measurements are all related to the primary key; the data in these columns represent an observation at a particular location at a particular time point.
However, we now have two tables rather than just one, so we must make sure that the tables are linked to each other, and in order to achieve this, we need to determine the relationships between the tables. NoSQL Distilled: Refactoring Databases: Database in Depth: Relational Theory for Practitioners Paperback by C. Java Persistence with Hibernate: Redis in Action Paperback by Josiah L.
Up and Running Paperback by Regina O. The Data Warehouse Lifecycle Toolkit: Graph Databases Paperback by Ian Robinson. PostgreSQL 9.
Transaction Processing: Concepts and Techniques Hardcover by Jim Gray. Database Systems: Want something new? Trying to fill a Read Harder challenge that depends on author background?
You can also limit by audience age. First, select a category that identifies a particular element of a book—things like tone, character, and pace.
Then, find a word that describes what kind of tone, for example, you like: Want a list of books around a given topic? NoveList has it and can direct you as to where to get started. Beauty and the Beast:Notice that the information in the publisher and country columns is identical for the books published by Mallinson Rendel. The audio books are always available to subscribing libraries and their patrons.
Databases, Types, and the Relational Model: A possible redesign that satisfies the requirement that each column is atomic and not duplicative is shown below. However, normalization may produce a database that is slow in terms of accessing the data because the data from many tables has to be recombined. Title, author, start date, stop date. The notation that we will use is a simple text description, with primary keys and foreign keys indicated in square brackets.
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