Home > Articles > Web Development

  • Print
  • + Share This
This chapter is from the book

Gadfly—Zope's Integrated Demo Relational Database

Gadfly is a simple RDBMS that comes with Zope. Its features and possibilities cannot compete with any of the previously mentioned RDBMSs, but it is sufficient for testing purposes. This RDBMS is written entirely in Python and supports the basic RDBMS Structured Query Language (SQL).

Gadfly can be run on any machine where Python is installed and is independent from the platform on which you are working. That allows you to copy the Gadfly directory via a binary stream from a Windows machine to a Linux machine.

Because Gadfly supports log-based recovery protocols, you can recover actions made in the database even if the database was not shut down properly.

Establishing a Gadfly Database Connection

Before you can use the Gadfly database, a database connection needs to be established. This is done by creating an instance of the database adapter in Zope.

To create an instance of the Gadfly Database Connection, choose Z Gadfly Database Connection from the drop-down menu in the Zope Management screen. Your browser will automatically be directed to the page shown in Figure 3.2.

Figure 3.2 Add a Z Gadfly Database Connection.

Fill out the form with the following data:

ID: MyGadflyDatabaseConnection
Title: Demo Z Gadfly Database

Now, select Demo from the list of data sources, make sure the box to the right of Connect Immediately? is checked, and press the Add button. The database connection is created and the connection to the database is automatically opened. Your browser is now directed back to the Content view of your root folder where you can see the new instance of the database connection, as shown in Figure 3.3.

Figure 3.3 The instance of the Z Gadfly Database Connection.

NOTE

Whenever you create objects in Zope, you have to give the object an ID. This ID cannot contain spaces or special characters that are invalid in URLs because the ID is used as an URL to the respective object. You need not choose a title for a new object, but it sometimes makes it easier to have a short description for a title.

The Different Views of the Database Connection

If you click MyGadflyDatabaseConnection, you are directed to the Status View of the database connection. This is the default view for this type of object.

Status View

This view shows you the status of the respective database connection. For example, it tells you whether the database connection is open or closed, as seen in Figure 3.4. You can also change that status by clicking Close Connection or Open Connection. The name of the button changes depending on the status of the connection.

Properties View

The Properties View (see Figure 3.5) allows you to change the properties of the database connection. The properties include the title, the source for the connection, and whether the connection is to be established immediately.

You can use one instance of the Z Gadfly Database Connection to connect to different databases, but only one database at a time. If you want to create a new database called something other than Demo, see the "How to Create Different Z Gadfly Databases" section later in this chapter.

Figure 3.4 Status View of the database connection.

Figure 3.5 Properties View of the database connection.

Test View

This view allows you to test SQL statements. Enter the SQL query in the text area and click the Submit Query button (see Figure 3.6). The query will be sent to the database and executed. In this way, you can test SQL statements without creating Z SQL methods.

Figure 3.6 Test View of the database connection.

Figure 3.7 shows the result of your query—if there is any. Below the result, the view shows the statement used.

Security View

The Security View (see Figure 3.8) exists in most objects in Zope. It is used to create new roles or change the permission settings for the existing roles. It also contains a link to another page where local roles can be set. The list of permissions depend on whether you look at the Security View of a folder or of a non-folder object. Folder objects such as a folder or a Z Discussion can contain other objects.

Figure 3.7 Result of a submitted SQL query.

Figure 3.8 Security View of the database connection.

Undo View

The Undo View (see Figure 3.9) is another view that is common with most Zope objects. Here, you can undo actions made in the current folder or one of its subfolders. Select the actions you want to undo and then click the Undo button below the list of actions.

Figure 3.9 Undo View of the database connection.

Ownership View

The Ownership View is also a common view in Zope (see Figure 3.10). It states either who created the current object or who took over the ownership of the object. When you create a new object in Zope, Zope registers you as the owner of this object.

However, any Zope user who has the role Owner, or whose role has the permission Take Ownership, can take over ownership of any object in Zope. Taking over ownership is done via the Ownership View. If you are allowed to take ownership, the Ownership View will look like Figure 3.11.

Figure 3.10 The Ownership View where the object is owned by the manager.

Figure 3.11 The Ownership View with the Take Ownership button.

Having ownership of an object can be important when executing methods in Zope.

Browse View

In the Browse View, you can see—and browse through—the content of the tables and rows that exist in the database that the Z Gadfly Database Connection is currently connected to (the data source of the connection). The view shows the name of the tables and the rows in the tables. It also shows the type of the rows. Figure 3.12 shows the Testtable table that contains three rows: Name, First_name, and Age. The types are shown by the images in front of the row names and the type names after the row names.

Figure 3.12 Browse View of the database connection.

NOTE

At the time of writing, the Z Gadfly Database only supports the VARCHAR, INTEGER, and FLOAT field types. This is another reason why the Z Gadfly Database is only suitable for test purposes.

How to Create Different Z Gadfly Databases

When you created the Z Gadfly Database Connection earlier in the chapter, you selected the Demo database to be used with this connection. As mentioned before, you can use more than one database with a connection, but only one database at a time.

To create a new database that you can use with any Z Gadfly Database Connection, go to the /var/gadfly folder in your Zope installation folder. There you will find a subfolder /demo, which is where anything you have done so far with the demo database is being stored. Now, you just need to create a new folder in the /gadfly folder, and you can start creating tables in the new database.

You can either create a new Z Gadfly Database Connection for the new database and select the name of the new folder instead of Demo, or you can use the existing Z Gadfly Database Connection and change the data source in the Properties View.

  • + Share This
  • 🔖 Save To Your Account

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.

Overview


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information


To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.

Surveys

Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.

Newsletters

If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information


Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.

Security


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.

Children


This site is not directed to children under the age of 13.

Marketing


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information


If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.

Choice/Opt-out


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information


Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents


California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure


Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.

Links


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact


Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice


We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020