Home > Articles > Data > Oracle

  • Print
  • + Share This
Like this article? We recommend Application Design

Application Design

Now that we have an optimal data model and index set, how do we construct the application to make best use of the database? There are probably three main considerations that affect application design:

  • Reduce unnecessary SQL requests, by remembering (caching) data and reducing SQL statement parsing.
  • Reduce network round trips, either by using stored procedures or by exploiting the array interface.
  • Reduce lock contention though sensible transaction design and locking strategies.


The less SQL we send, the lower our database overhead. For most applications, reducing SQL is achieved by caching frequently accessed static data.

Oracle 11g allows us to get the benefits from client-side data caching without the need to implement our own client-side caching code. The 11g client-side result set cache—officially known as the OCI consistent client cache—stores recently retrieved result sets in the client’s memory. If a client program—SQL*PLUS, java, C# or whatever—issues the same query twice within a certain interval, the client-side cache can return the previously fetched result set without sending the query to the database server.

However you implement caching, be careful not to cache data that is volatile—slow data is usually better than wrong data.

Reducing Parsing

Parsing is the process of preparing a SQL statement for execution, and involves checking syntax and permissions as well as creating an execution plan, which describes the step-by-step process Oracle will undertake to resolve the SQL statement.

Oracle maintains a cache of SQL statements in the shared pool. If a matching SQL is found in the shared pool, then most of the parse overhead can be avoided; this is a soft parse. If no matching SQL is found, a hard parse must be performed.

Hard parsing is expensive, and also is one of the most common causes of latch contention. You avoid hard parsing primarily through the use of bind variables. In Java, you do this by using preparedStatements with placeholders for the variable parts of the SQL. In C# (using ODP.NET), you add Parameters to the OracleCommand objects. Other languages (Perl, Python, Ruby, etc.) use different idioms to support bind variables.

If all else fails, the database CURSOR_SHARING parameter can be set to SIMILAR or FORCE to have bind variables automatically inserted into your SQLs by Oracle.

Array Processing

When fetching or inserting rows, Oracle allows the application to fetch or insert more than one row at a time. This reduces the number of calls issued to the database server, and can also reduce network traffic and logical IO overhead.

In JDBC, array fetch is as simple as setting the setFetchSize property of the statement. In other languages, or when performing array insert, the procedure can be more complex, but still well worth the effort. Figure 3 shows how using array fetch can improve performance.

Figure 3 Effects of increasing array size on table scan performance

Stored Procedures

Another way to optimize network traffic is to use stored procedures. A complex transaction may involve many individual SQL statements. If these SQL statements are sent from a remote application each execution will involve a network round trip and network overhead can easily dominate response time.

If the transaction is encapsulated in a stored procedure, then these round trips can be eliminated, and network overhead minimized.

Transaction Design

The need to maintain transactional integrity requires that Oracle sometimes prevent SQLs from executing simultaneously by using blocking locks.

Application transaction design should aim to hold locks for the least possible amount of time, although you should almost never sacrifice transactional integrity to achieve this. One of the most significant design decisions that affect lock duration will be the decision between employing the optimistic locking strategy and the pessimistic locking strategy.

The pessimistic locking strategy is based on an assumption that it is likely that a row will be updated by another user between the time you fetch it and the time you update it. To avoid any contention, the pessimistic locking strategy requires that you lock the rows as they are retrieved.

The optimistic locking strategy is based on the assumption that it is very unlikely that an update will be applied to a row between the time it is retrieved and the time it is modified. Based on this assumption, the optimistic locking strategy does not require that the row be locked when fetched, but it will be necessary to check that the row has not been changed by another session when being modified or locked later.

The optimistic strategy tends to hold locks for a shorter duration, though it can back-fire if another transaction breaks the optimistic assumption. Figure 4 compares the two approaches.

Figure 4 The optimistic and pessimistic locking strategies.

  • + 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.


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.


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.


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.


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


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


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.


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.


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