Abstract:
In accordance with embodiments, there are provided mechanisms and methods for debugging an assertion. These mechanisms and methods for debugging an assertion can enable improved interpretation and analysis of data validation results, more efficient development associated with data validation, etc.

Description:
CLAIM OF PRIORITY 
       [0001]    This application claims the benefit of U.S. Provisional Patent Application 61/320,118, entitled “Federated Single-Sign-On Debugger in a Multi-tenant Environment,” by Lee et al., filed Apr. 1, 2010 (Attorney Docket No. SEC1P091+/272PROV), the entire contents of which are incorporated herein by reference. 
     
    
     COPYRIGHT NOTICE 
       [0002]    A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever. 
       FIELD OF THE INVENTION 
       [0003]    One or more implementations relate generally to data validation, and more particularly to debugging data used for validation. 
       BACKGROUND 
       [0004]    The subject matter discussed in the background section should not be assumed to be prior art merely as a result of its mention in the background section. Similarly, a problem mentioned in the background section or associated with the subject matter of the background section should not be assumed to have been previously recognized in the prior art. The subject matter in the background section merely represents different approaches, which in and of themselves may also be inventions. 
         [0005]    Data validation is a common practice of conventional systems. For example, a first login service may desire to validate a user login with a second login service (e.g., in a single sign-on environment, etc.). Unfortunately, conventional validation techniques have been associated with various limitations. 
         [0006]    Just by way of example, traditional methods of validating a user login with a login service may require a specific format that may prove difficult to follow. Additionally, any errors encountered during the validation may result in cryptic error codes that may prove difficult and time-consuming to manually interpret and address. Further, errors encountered during the validation may stop the validation process from continuing. Accordingly, it is desirable to provide techniques that improve the interpretation and analysis of conventional validation techniques. 
       BRIEF SUMMARY 
       [0007]    In accordance with embodiments, there are provided mechanisms and methods for debugging an assertion. These mechanisms and methods for debugging an assertion can enable improved interpretation and analysis of data validation results, more efficient development associated with data validation, etc. 
         [0008]    In an embodiment and by way of example, a method for debugging an assertion is provided. In one embodiment, an assertion is received at a debugger. Additionally, the assertion is debugged, utilizing the debugger. Further, results of the debugging are returned. 
         [0009]    While one or more implementations and techniques are described with reference to an embodiment in which debugging an assertion is implemented in a system having an application server providing a front end for an on-demand database system capable of supporting multiple tenants, the one or more implementations and techniques are not limited to multi-tenant databases nor deployment on application servers. Embodiments may be practiced using other database architectures, i.e., ORACLE®, DB2® by IBM and the like without departing from the scope of the embodiments claimed. 
         [0010]    Any of the above embodiments may be used alone or together with one another in any combination. The one or more implementations encompassed within this specification may also include embodiments that are only partially mentioned or alluded to or are not mentioned or alluded to at all in this brief summary or in the abstract. Although various embodiments may have been motivated by various deficiencies with the prior art, which may be discussed or alluded to in one or more places in the specification, the embodiments do not necessarily address any of these deficiencies. In other words, different embodiments may address different deficiencies that may be discussed in the specification. Some embodiments may only partially address some deficiencies or just one deficiency that may be discussed in the specification, and some embodiments may not address any of these deficiencies. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    In the following drawings like reference numbers are used to refer to like elements. Although the following figures depict various examples, the one or more implementations are not limited to the examples depicted in the figures. 
           [0012]      FIG. 1  illustrates a method for debugging an assertion, in accordance with one embodiment; 
           [0013]      FIG. 2  illustrates a system and method for initiating debugging of an assertion, in accordance with another embodiment; 
           [0014]      FIG. 3  illustrates a block diagram of an example of an environment wherein an on-demand database system might be used; and 
           [0015]      FIG. 4  illustrates a block diagram of an embodiment of elements of  FIG. 4  and various possible interconnections between these elements. 
       
    
    
     DETAILED DESCRIPTION 
     General Overview 
       [0016]    Systems and methods are provided for debugging an assertion. 
         [0017]    As used herein, the term multi-tenant database system refers to those systems in which various elements of hardware and software of the database system may be shared by one or more customers. For example, a given application server may simultaneously process requests for a great number of customers, and a given database table may store rows for a potentially much greater number of customers. 
         [0018]    Next, mechanisms and methods for debugging an assertion will be described with reference to example embodiments. 
         [0019]      FIG. 1  illustrates a method  100  for debugging an assertion, in accordance with one embodiment. As shown in operation  102 , an assertion is received at a debugger. In one embodiment, the assertion may include a message. For example, the assertion may include a request to verify one or more elements of data. In another example, the assertion may include a request to log a user into the system. In another embodiment, the assertion may include one or more elements of data. For example, the assertion may include a user name, a timestamp, a certificate (e.g., an authorization certificate, etc.), etc. 
         [0020]    In yet another embodiment, the assertion may be encoded (e.g., utilizing Extensible Markup Language (XML), base64 encoding, etc.). Further, in one embodiment, the assertion may be sent from one entity (e.g., a server, a multi-tenant on-demand database system, etc.) to another entity. For example, a user may be associated with a first entity (e.g., logged into the first entity, verified by the first entity, etc.), and may desire to log into a second entity. Additionally, the assertion may be sent from the second entity to the first entity in an attempt to verify the user and log the user into the second entity. 
         [0021]    In another embodiment, the assertion may be of a specific file type. For example, the assertion may include an Extensible Markup Language (XML) file, a base64 encoded format file, etc. In yet another embodiment, the assertion may be associated with a user of an entity (e.g., a client, a server, a multi-tenant on-demand database system, etc.). For example, the assertion may be associated with a particular user of an organization of a multi-tenant on-demand database system. 
         [0022]    Additionally, in one embodiment, the debugger may include software that is installed on an entity. For example, the debugger may be installed on a client, a server, a cloud, a multi-tenant on-demand database system, etc. In another embodiment, the assertion may be received at the debugger if the assertion fails to be validated. For example, the assertion may be received at the debugger if one or more errors are detected during the validation of the assertion (e.g., at the entity, etc.). In yet another embodiment, the debugger may intercept the assertion. For example, a first system may send the assertion to a second system, where the debugger is installed on the second system. Further, the debugger may intercept the assertion at the second system. 
         [0023]    Also, in one embodiment, the assertion may be cached (e.g., at the system where the debugger is installed) before or after processing the assertion and may be sent to the debugger if an issue is found while processing (e.g., parsing, etc.) the assertion at the system. For example, one or more errors may be determined during the processing of the assertion at the system, and the cached assertion may be sent to the debugger as a result of determining the errors. In another example, the cached assertion may be sent to the debugger in response to the user launching a debugger page. In another embodiment, the cached assertion may be associated with a user of the system, and the debugger may be automatically populated with the assertion based on the user&#39;s information within the system. Further, in another embodiment, the assertion may be recreated. For example, the assertion may be recreated in response to a request (e.g., by a user, by the debugger, etc.), and may be input into the debugger. 
         [0024]    Further still, in one embodiment, the assertion may be input into the debugger utilizing a user interface (UI). For example, the text of the assertion may be copied and pasted into a field of a UI page associated with the debugger, and may be submitted to the debugger once a button is selected on the UI page (e.g., a “validate” button, etc.). In another embodiment, the assertion may be input into the debugger as part of an initial setup. 
         [0025]    Additionally, it should be noted that, as described above, such multi-tenant on-demand database system may include any service that relies on a database system that is accessible over a network, in which various elements of hardware and software of the database system may be shared by one or more customers (e.g. tenants). For instance, a given application server may simultaneously process requests for a great number of customers, and a given database table may store rows for a potentially much greater number of customers. Various examples of such a multi-tenant on-demand database system will be set forth in the context of different embodiments that will be described during reference to subsequent figures. 
         [0026]    Furthermore, as shown in operation  104 , the assertion is debugged, utilizing the debugger. In one embodiment, debugging the assertion may include monitoring the validation of the assertion by the debugger. For example, the debugger may monitor each step of the system validation process while the system validates the assertion (e.g., utilizing a validator of the system, etc.). Additionally, in another embodiment, the debugger may record one or more errors that occur during the validation of the assertion. For example, the validation of the assertion may include checking a plurality of elements associated with the assertion (e.g., a time of a last login, a time stamp, a certificate, a username, etc.), and one or more errors may occur if one or more of the elements of the assertion are found to be invalid. Additionally, these errors may be recorded by the debugger. In another embodiment, the one or more errors may each be represented by an error code, an error condition, etc. 
         [0027]    In yet another embodiment, the debugging may continue after an error is encountered during validation. For example, instead of exiting after a first error is discovered during validation, the error may be logged and the debugging and validation may continue until all elements associated with the assertion are checked. In another embodiment, overrides may be used to continue running the validator even when an error is found. In this way, the entirety of the assertion may be debugged in one pass. Additionally, in one embodiment, the debugging may include associating the one or more errors with a user of the system. 
         [0028]    Also, as shown in operation  106 , results of the debugging are returned. In one embodiment, the results may include the results of every step of the validation that was monitored by the debugger, along with an indication of whether each step caused an error vas successful, depending on whether the validation passed or failed for that step. In another embodiment, the results of the debugging may be displayed utilizing an interface. For example, the results may be displayed to a user, administrator, etc. via a user interface. 
         [0029]    In yet another embodiment, the results of the debugging may include one or more translated error codes. For example, the debugger may translate an error code that was discovered during the debugging into a natural language description of the error that may include details such as a specific description of an error (e.g., “user does not exist,” etc.), a likely cause of the error (e.g., “time stamp was five hours out of date,” etc.), a possible solution for the error (e.g., “need to account for different time zone,” etc.), etc. In another embodiment, the error codes may be displayed in addition to their translations. In this way, the recipient of the results of the debugging may be able to easily understand what errors occurred during the validation, and what errors need to be addressed in the assertion. 
         [0030]    In yet another embodiment, the results of the debugging may include one or more symbols or colors associated with the results. For example, one or more green bars may be associated with elements of the assertion that did not cause an error during debugging. In another example, one or more red bars may be associated with elements of the assertion that did cause an error during debugging. Further, in another embodiment, the results of the debugging may include a report. For example, a report may be returned that lists every element of the assertion, along with an indication of whether the element caused an error during debugging. 
         [0031]    Additionally, in one embodiment, the results of the debugging may be sent as an electronic mail message (e.g., to an administrator, to a user associated with the assertion, etc.). In yet another embodiment, the results of the debugging may be presented to a user when they log into an organization of the system. In still another embodiment, one or more additional actions may be performed, based on the results. For example, if one or more particular errors are detected during the debugging (e.g., an expired certificate, etc.), or if one or more particular errors are detected multiple times over a predetermined time period (e.g., signifying a malicious system attack, etc.), an email alert may be sent (e.g., to a system administrator, etc.). 
         [0032]    In this way, a user may be provided with a debugger resource where they can simply enter an assertion in a field, press a button, and determined whether the assertion would have been accepted by the system. Additionally, error messages provided as a result of the debugging may be clear and explanatory, and less cryptic than a generic numerical error code. Further, all elements of the assertion may be debugged at once, even if errors are encountered before all elements are debugged. 
         [0033]      FIG. 2  illustrates a system and method  200  for initiating debugging of an assertion, in accordance with another embodiment. As an option, the present system and method  200  may be carried out in the context of the functionality of  FIG. 1 . Of course, however, the system and method  200  may be carried out in any desired environment. The aforementioned definitions may apply during the present description. 
         [0034]    As shown in operation  202 , an entity  220  attempts to sign on (e.g., log in, etc.) to a system cloud  222  by sending the system cloud  222  an assertion (e.g., an encoded security association markup language (SAML) assertion, etc.). In one embodiment, the assertion may be associated with a user. For example, the user may be currently logged into the entity  220 . In another example, the entity may send the assertion in an attempt to log the user on to the system cloud  222 . In yet another example, the assertion may ask the system cloud  222  whether a user exists, whether the user is valid, whether the user has one or more permissions, etc. In this way, the entity may request a determination of whether the user has been verified by the system cloud  222 . 
         [0035]    Additionally, as shown in operation  204 , it is determined that the attempt to sign on to the system cloud has failed, and the assertion is pushed to the failure cache  224 . In one embodiment, the failure cache  224  may be associated with an organization. For example, the failure cache  224  may be located in an organization associated with the user. In another embodiment, the assertion is stored at the failure cache  224 . 
         [0036]    Further, as shown in operation  206 , the entity  220  receives a failed result from the system cloud  222 . For example, the entity  220  may receive an indication from the system cloud  222  that the user could not be verified, that the user could not be logged in to the system cloud  222 , etc. Further still, as shown in operation  208 , an administrator  226  launches a debugger at the system cloud  222 . In one embodiment, the administrator  226  may launch the debugger in response to the failed result sent to the entity  220 . In another embodiment, the administrator  226  may be in charge of setting up the communication procedure between the entity  220  and the system cloud  222 , In yet another embodiment, the administrator  226  may launch the debugger from a user interface located at the system cloud  222 . 
         [0037]    Also, as shown in operation  210 , the assertion is popped from the failure cache  224  and is automatically populated into a debugger within the system cloud  222 . In one embodiment, the debugger may debug the assertion sent from the failure cache  224  and may return results of the debugging to the administrator  226 . In this way, the administrator  226  may be able to easily initiate the debugging of a failed login assertion within the system cloud  222 . 
       System Overview 
       [0038]      FIG. 3  illustrates a block diagram of an environment  310  wherein an on-demand database system might be used. Environment  310  may include user systems  312 , network  314 , system  316 , processor system  317 , application platform  318 , network interface  320 , tenant data storage  322 , system data storage  324 , program code  326 , and process space  328 . In other embodiments, environment  310  may not have all of the components listed and/or may have other elements instead of, or in addition to, those listed above. 
         [0039]    Environment  310  is an environment in which an on-demand database system exists. User system  312  may be any machine or system that is used by a user to access a database user system. For example, any of user systems  312  can be a handheld computing device, a mobile phone, a laptop computer, a work station, and/or a network of computing devices. As illustrated in  FIG. 3  (and in more detail in  FIG. 4 ) user systems  312  might interact via a network  314  with an on-demand database system, which is system  316 . 
         [0040]    An on-demand database system, such as system  316 , is a database system that is made available to outside users that do not need to necessarily be concerned with building and/or maintaining the database system, but instead may be available for their use when the users need the database system (e.g., on the demand of the users). Some on-demand database systems may store information from one or more tenants stored into tables of a common database image to form a multi-tenant database system (MTS). Accordingly, “on-demand database system  316 ” and “system  316 ” will be used interchangeably herein. A database image may include one or more database objects. A relational database management system (RDMS) or the equivalent may execute storage and retrieval of information against the database object(s). Application platform  318  may be a framework that allows the applications of system  316  to run, such as the hardware and/or software, e.g., the operating system. In an embodiment, on-demand database system  316  may include an application platform  318  that enables creation, managing and executing one or more applications developed by the provider of the on-demand database system, users accessing the on-demand database system via user systems  312 , or third party application developers accessing the on-demand database system via user systems  312 . 
         [0041]    The users of user systems  312  may differ in their respective capacities, and the capacity of a particular user system  312  might be entirely determined by permissions (permission levels) for the current user. For example, where a salesperson is using a particular user system  312  to interact with system  316 , that user system has the capacities allotted to that salesperson. However, while an administrator is using that user system to interact with system  316 , that user system has the capacities allotted to that administrator. In systems with a hierarchical role model, users at one permission level may have access to applications, data, and database information accessible by a lower permission level user, but may not have access to certain applications, database information, and data accessible by a user at a higher permission level. Thus, different users will have different capabilities with regard to accessing and modifying application and database information, depending on a user&#39;s security or permission level. 
         [0042]    Network  314  is any network or combination of networks of devices that communicate with one another. For example, network  314  can be any one or any combination of a LAN (local area network), WAN (wide area network), telephone network, wireless network, point-to-point network, star network, token ring network, hub network, or other appropriate configuration. As the most common type of computer network in current use is a TCP/IP (Transfer Control Protocol and Internet Protocol) network, such as the global internetwork of networks often referred to as the “Internet” with a capital “I,” that network will be used in many of the examples herein, However, it should be understood that the networks that the one or more implementations might use are not so limited, although TCP/IP is a frequently implemented protocol. 
         [0043]    User systems  312  might communicate with system  316  using TCP/IP and, at a higher network level, use other common Internet protocols to communicate, such as HTTP, FTP, AFS, WAP, etc. In an example where HTTP is used, user system  312  might include an HTTP client commonly referred to as a “browser” for sending and receiving HTTP messages to and from an HTTP server at system  316 . Such an HTTP server might be implemented as the sole network interface between system  316  and network  314 , but other techniques might be used as well or instead. In some implementations, the interface between system  316  and network  314  includes load sharing functionality, such as round-robin HTTP request distributors to balance loads and distribute incoming HTTP requests evenly over a plurality of servers. At least as for the users that are accessing that server, each of the plurality of servers has access to the MTS&#39; data; however, other alternative configurations may be used instead. 
         [0044]    In one embodiment, system  316 , shown in  FIG. 3 , implements a web-based customer relationship management (CRM) system. For example, in one embodiment, system  316  includes application servers configured to implement and execute CRM software applications as well as provide related data, code, forms, webpages and other information to and from user systems  312  and to store to, and retrieve from, a database system related data, objects, and Webpage content. With a multi-tenant system, data for multiple tenants may be stored in the same physical database object, however, tenant data typically is arranged so that data of one tenant is kept logically separate from that of other tenants so that one tenant does not have access to another tenant&#39;s data, unless such data is expressly shared. In certain embodiments, system  316  implements applications other than, or in addition to, a CRM application. For example, system  316  may provide tenant access to multiple hosted (standard and custom) applications, including a CRM application. User (or third party developer) applications, which may or may not include CRM, may be supported by the application platform  318 , which manages creation, storage of the applications into one or more database objects and executing of the applications in a virtual machine in the process space of the system  316 . 
         [0045]    One arrangement for elements of system  316  is shown in  FIG. 3 , including a network interface  320 , application platform  318 , tenant data storage  322  for tenant data  323 , system data storage  324  for system data  325  accessible to system  316  and possibly multiple tenants, program code  326  for implementing various functions of system  316 , and a process space  328  for executing MTS system processes and tenant-specific processes, such as running applications as part of an application hosting service. Additional processes that may execute on system  316  include database indexing processes. 
         [0046]    Several elements in the system shown in  FIG. 3  include conventional, well-known elements that are explained only briefly here. For example, each user system  312  could include a desktop personal computer, workstation, laptop, PDA, cell phone, or any wireless access protocol (WAR) enabled device or any other computing device capable of interfacing directly or indirectly to the Internet or other network connection. User system  312  typically runs an HTTP client, e.g., a browsing program, such as Microsoft&#39;s Internet Explorer browser, Netscape&#39;s Navigator browser, Opera&#39;s browser, or a WAR-enabled browser in the case of a cell phone, PDA or other wireless device, or the like, allowing a user (e.g., subscriber of the multi-tenant database system) of user system  312  to access, process and view information, pages and applications available to it from system  316  over network  314 . Each user system  312  also typically includes one or more user interface devices, such as a keyboard, a mouse, trackball, touch pad, touch screen, pen or the like, for interacting with a graphical user interface (GUI) provided by the browser on a display (e.g., a monitor screen, LCD display, etc.) in conjunction with pages, forms, applications and other information provided by system  316  or other systems or servers. For example, the user interface device can be used to access data and applications hosted by system  316 , and to perform searches on stored data, and otherwise allow a user to interact with various GUI pages that may be presented to a user. As discussed above, embodiments are suitable for use with the Internet, which refers to a specific global internetwork of networks. However, it should be understood that other networks can be used instead of the Internet, such as an intranet, an extranet, a virtual private network (VPN), a non-TCP/IP based network, any LAN or WAN or the like. 
         [0047]    According to one embodiment, each user system  312  and all of its components are operator configurable using applications, such as a browser, including computer code run using a central processing unit such as an Intel Pentium® processor or the like. Similarly, system  316  (and additional instances of an NITS, where more than one is present) and all of their components might be operator configurable using application(s) including computer code to run using a central processing unit such as processor system  317 , which may include an Intel Pentium® processor or the like, and/or multiple processor units. A computer program product embodiment includes a machine-readable storage medium (media) having instructions stored thereon/in which can be used to program a computer to perform any of the processes of the embodiments described herein. Computer code for operating and configuring system  316  to intercommunicate and to process webpages, applications and other data and media content as described herein are preferably downloaded and stored on a hard disk, but the entire program code, or portions thereof, may also be stored in any other volatile or non-volatile memory medium or device as is well known, such as a ROM or RAM, or provided on any media capable of storing program code, such as any type of rotating media including floppy disks, optical discs, digital versatile disk (DVD), compact disk (CD), microdrive, and magneto-optical disks, and magnetic or optical cards, nanosystems (including molecular memory ICs), or any type of media or device suitable for storing instructions and/or data. Additionally, the entire program code, or portions thereof, may be transmitted and downloaded from a software source over a transmission medium, e.g., over the Internet, or from another server, as is well known, or transmitted over any other conventional network connection as is well known (e.g., extranet, VPN, LAN, etc.) using any communication medium and protocols (e.g., TCP/IP, HTTP, HTTPS, Ethernet, etc.) as are well known. It will also be appreciated that computer code for implementing embodiments can be implemented in any programming language that can be executed on a client system and/or server or server system such as, for example, C, C++, HTML, any other markup language, Java™, JavaScript, ActiveX, any other scripting language, such as VBScript, and many other programming languages as are well known may be used. (Java™ is a trademark of Sun Microsystems, Inc.). 
         [0048]    According to one embodiment, each system  316  is configured to provide webpages, forms, applications, data and media content to user (client) systems  312  to support the access by user systems  312  as tenants of system  316 . As such, system  316  provides security mechanisms to keep each tenant&#39;s data separate unless the data is shared. If more than one MTS is used, they may be located in close proximity to one another (e.g., in a server farm located in a single building or campus), or they may be distributed at locations remote from one another (e.g., one or more servers located in city A and one or more servers located in city B). As used herein, each MTS could include one or more logically and/or physically connected servers distributed locally or across one or more geographic locations. Additionally, the term “server” is meant to include a computer system, including processing hardware and process space(s), and an associated storage system and database application (e.g., OODBMS or RDBMS) as is well known in the art. It should also be understood that “server system” and “server” are often used interchangeably herein. Similarly, the database object described herein can be implemented as single databases, a distributed database, a collection of distributed databases, a database with redundant online or offline backups or other redundancies, etc., and might include a distributed database or storage network and associated processing intelligence. 
         [0049]      FIG. 4  also illustrates environment  310 . However, in  FIG. 4  elements of system  316  and various interconnections in an embodiment are further illustrated.  FIG. 4  shows that user system  312  may include processor system  312 A, memory system  312 B, input system  312 C, and output system  312 D.  FIG. 4  shows network  314  and system  316 .  FIG. 4  also shows that system  316  may include tenant data storage  322 , tenant data  323 , system data storage  324 , system data  325 , User interface (UI)  430 , Application Program interface (API)  432 , PL/SOQL  434 , save routines  436 , application setup mechanism  438 , applications servers  400   1 - 400   N , system process space  402 , tenant process spaces  404 , tenant management process space  410 , tenant storage area  412 , user storage  414 , and application metadata  416 . In other embodiments, environment  310  may not have the same elements as those listed above and/or may have other elements instead of, or in addition to, those listed above. 
         [0050]    User system  312 , network  314 , system  316 , tenant data storage  322 , and system data storage  324  were discussed above in  FIG. 3 . Regarding user system  312 , processor system  312 A may be any combination of one or more processors. Memory system  312 B may be any combination of one or more memory devices, short term, and/or long term memory. Input system  312 C may be any combination of input devices, such as one or more keyboards, mice, trackballs, scanners, cameras, and/or interfaces to networks. Output system  312 D may be any combination of output devices, such as one or more monitors, printers, and/or interfaces to networks. As shown by  FIG. 4 , system  316  may include a network interface  320  (of  FIG. 3 ) implemented as a set of HTTP application servers  400 , an application platform  318 , tenant data storage  322 , and system data storage  324 . Also shown is system process space  402 , including individual tenant process spaces  404  and a tenant management process space  410 . Each application server  400  may be configured to tenant data storage  322  and the tenant data  323  therein, and system data storage  324  and the system data  325  therein to serve requests of user systems  312 . The tenant data  323  might be divided into individual tenant storage areas  412 , which can be either a physical arrangement and/or a logical arrangement of data. Within each tenant storage area  412 , user storage  414  and application metadata  416  might be similarly allocated for each user. For example, a copy of a user&#39;s most recently used (MRU) items might be stored to user storage  414 . Similarly, a copy of MRU items for an entire organization that is a tenant tnight be stored to tenant storage area  412 . A UI  430  provides a user interface and an API  432  provides an application programmer interface to system  316  resident processes to users and/or developers at user systems  312 . The tenant data and the system data may be stored in various databases, such as one or more Oracle™ databases. 
         [0051]    Application platform  318  includes an application setup mechanism  438  that supports application developers&#39; creation and management of applications, which may be saved as metadata into tenant data storage  322  by save routines  436  for execution by subscribers as one or more tenant process spaces  404  managed by tenant management process  410  for example. Invocations to such applications may be coded using PL/SOQL  434  that provides a programming language style interface extension to API  432 . A detailed description of some PL/SOQL language embodiments is discussed in commonly owned co-pending U.S. Provisional Patent Application 60/828,192 entitled, PROGRAMMING LANGUAGE METHOD AND SYSTEM FOR EXTENDING APIS TO EXECUTE IN CONJUNCTION WITH DATABASE APIS, by Craig Weissman, filed Oct. 4, 2006, which is incorporated in its entirety herein for all purposes. Invocations to applications may be detected by one or more system processes, which manages retrieving application metadata  416  for the subscriber makingthe invocation and executing the metadata as an application in a virtual machine. 
         [0052]    Each application server  400  may be communicably coupled to database systems, e.g., having access to system data  325  and tenant data  323 , via a different network connection. For example, one application server  400   1  might be coupled via the network  314  (e.g., the Internet), another application server  400   N-1  might be coupled via a direct network link, and another application server  400   N  might be coupled by yet a different network connection, Transfer Control Protocol and Internet Protocol (TCP/IP) are typical protocols for communicating between application servers  400  and the database system. However, it will be apparent to one skilled in the art that other transport protocols may be used to optimize the system depending on the network interconnect used. 
         [0053]    In certain embodiments, each application server  400  is configured to handle requests for any user associated with any organization that is a tenant. Because it is desirable to be able to add and remove application servers from the server pool at any time for any reason, there is preferably no server affinity for a user and/or organization to a specific application server  400 . In one embodiment, therefore, an interface system implementing a load balancing function (e.g., an F5 Big-IP load balancer) is communicably coupled between the application servers  400  and the user systems  312  to distribute requests to the application servers  400 . In one embodiment, the load balancer uses a least connections algorithm to route user requests to the application servers  400 . Other examples of load balancing algorithms, such as round robin and observed response time, also can be used. For example, in certain embodiments, three consecutive requests from the same user could hit three different application servers  400 , and three requests from different users could hit the same application server  400 . In this manner, system  316  is multi-tenant, wherein system  316  handles storage of and access to, different objects, data and applications across disparate users and organizations. 
         [0054]    As an example of storage, one tenant might be a company that employs a sales force where each salesperson uses system  316  to manage their sales process. Thus, a user might maintain contact data, leads data, customer follow-up data, performance data, goals and progress data, etc., all applicable to that user&#39;s personal sales process (e.g., in tenant data storage  322 ). In an example of a MTS arrangement, since all of the data and the applications to access, view, modify, report, transmit, calculate, etc., can be maintained and accessed by a user system having nothing more than network access, the user can manage his or her sales efforts and cycles from any of many different user systems. For example, if a salesperson is visiting a customer and the customer has Internet access in their lobby, the salesperson can obtain critical updates as to that customer while waiting for the customer to arrive in the lobby. 
         [0055]    While each user&#39;s data might be separate from other users&#39; data regardless of the employers of each user, some data might be organization-wide data shared or accessible by a plurality of users or all of the users for a given organization that is a tenant. Thus, there might be some data structures managed by system  316  that are allocated at the tenant level while other data structures might be managed at the user level. Because an MTS might support multiple tenants including possible competitors, the MTS should have security protocols that keep data, applications, and application use separate. Also, because many tenants may opt for access to an MTS rather than maintain their own system, redundancy, up-time, and backup are additional functions that may be implemented in the MTS. In addition to user-specific data and tenant specific data, system  316  might also maintain system level data usable by multiple tenants or other data. Such system level data might include industry reports, news, postings, and the like that are sharable among tenants. 
         [0056]    In certain embodiments, user systems  31  (which may be client systems) communicate with application servers  400  to request and update system-level and tenant-level data from system  316  that may require sending one or more queries to tenant data storage  322  and/or system data storage  324 . System  316  (e.g., an application server  400  in system  316 ) automatically generates one or more SQL statements (e.g., one or more SQL queries) that are designed to access the desired information. System data storage  324  may generate query plans to access the requested data from the database. 
         [0057]    Each database can generally be viewed as a collection of objects, such as a set of logical tables, containing data fitted into predefined categories. A “table” is one representation of a data object, and may be used herein to simplify the conceptual description of objects and custom objects. It should be understood that “table” and “object” may be used interchangeably herein. Each table generally contains one or more data categories logically arranged as columns or fields in a viewable schema. Each row or record of a table contains an instance of data for each category defined by the fields. For example, a CRM database may include a table that describes a customer with fields for basic contact information such as name, address, phone number, fax number, etc. Another table might describe a purchase order, including fields for information such as customer, product, sale price, date, etc. In some multi-tenant database systems, standard entity tables might be provided for use by all tenants. For CRM database applications, such standard entities might include tables for Account, Contact, Lead, and Opportunity data, each containing pre-defined fields. It should be understood that the word “entity” may also be used interchangeably herein with “object” and “table”. 
         [0058]    In some multi-tenant database systems, tenants may be allowed to create and store custom objects, or they may be allowed to customize standard entities or objects, for example by creating custom fields for standard objects, including custom index fields. U.S. patent application Ser. No. 10/817,161, filed Apr. 2, 2004, entitled “Custom Entities and Fields in a Multi-Tenant Database System”, and which is hereby incorporated herein by reference, teaches systems and methods for creating custom objects as well as customizing standard objects in a multi-tenant database system. In certain embodiments, for example, all custom entity data rows are stored in a single multi-tenant physical table, which may contain multiple logical tables per organization. It is transparent to customers that their multiple “tables” are in fact stored in one large table or that their data may be stored in the same table as the data of other customers. 
         [0059]    While one or more implementations have been described by way of example and in terms of the specific embodiments, it is to be understood that one or more implementations are not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements as would be apparent to those skilled in the art. Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.