Patent Publication Number: US-9411852-B2

Title: Techniques for processing group membership data in a multi-tenant database system

Description:
CLAIM OF PRIORITY 
     This continuation application is related to, and claims priority to, the utility application entitled “TECHNIQUES FOR PROCESSING GROUP MEMBERSHIP DATA IN A MULTI-TENANT DATABASE SYSTEM,” filed on Jul. 3, 2008, having an application Ser. No. of 12/167,991 , now U.S. Pat. No. 8,473,518, the entire contents of which are incorporated herein by reference. 
    
    
     COPYRIGHT NOTICE 
     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 
     The current invention relates generally to processing query statements on a multi-tenant on demand architecture in a database network system. 
     BACKGROUND 
     The subject matter discussed in the background section should not be assumed to be prior art merely as a result of its mentioned 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. 
     In conventional database systems, users access their data resources in one logical database. A user of such a conventional system typically retrieves data from and stores data on the system using the user&#39;s own systems. A user system might remotely access one of a plurality of server systems that might in turn access the database system. Data retrieval from the system might include the issuance of a query from the user system to the database system. The database system might process the request for information received in the query and sent to the user system information relevant to the request. The efficient retrieval of accurate information and subsequent delivery of this information to the user system has been and continues to be a goal of database systems. 
     Unfortunately, conventional database approaches might become inefficient if, for example, updating applications in the presence of complex data structures. A database system may also process a query relatively slowly if, for example, a relatively large number of users substantially concurrently access the database system. Accordingly, it is desirable to provide techniques enabling an owner of the database system to improve the ease of use of the database system. 
     BRIEF SUMMARY 
     In accordance with embodiments, there are provided techniques for processing group membership data in a multi-tenant database system. These mechanisms and methods for processing group membership data in a multi-tenant database system can enable embodiments to ease the burden of manipulation data when updating the database. It may also reduce the processing cycles required to process queries to the database. 
     In an embodiment and by way of example, a method of processing group membership data in a multi-tenant database system includes receiving a request for access to a sub-portion of content on the database system. The request has requester identification data. Groups are identified that have access to the sub-portion. Data stored on the database in first and second sets system is joined to identify member information associated with the groups. It is determined whether the requester identification data corresponds to the member information; and access is granted to the sub-portion in response to determining that the requester identification data corresponding to the member information. 
     The present invention is described with reference to an embodiment in which an apparatus processes group membership data in a multi-tenant on demand architecture. The application server provides a front end for an on-demand database service capable of supporting multiple tenants; the present invention is not limited to multi-tenant database systems nor deployment on application servers. Embodiments may be practiced using other database architectures, i.e., ORACLE®, DB2C® by IBM and the like without departing from the scope of the embodiments claimed. 
     Any of the above embodiments may be used alone or together with one another in any combination. Inventions 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 of the invention 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 of the invention do not necessarily address any of these deficiencies. In other words, different embodiments of the invention 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 
       In the following drawings like reference numbers are used to refer to like elements. Although the following figures depict various examples of the invention, the invention is not limited to the examples depicted in the figures. 
         FIG. 1  illustrates a representative architecture for processing group membership data in a multi-tenant database system in accordance with one embodiment of the present invention; 
         FIG. 2  is a simplified schematic view showing interrelationships between various groups and tenant representatives in accordance with the present invention; 
         FIG. 3  is an operational flow diagram illustrating a high level overview of a method for controlling access to a multi-tenant database system using a virtual portal in one embodiment; 
         FIG. 4  is an operational flow diagram illustrating a high level overview of processing group membership in a multi-tenant database in accordance with a second embodiment of the present invention; 
         FIG. 5  illustrates a block diagram of an example of a representative system in which the architecture, shown in  FIG. 1 . may be practiced; 
         FIG. 6  is a detail block diagram of a user system, shown in  FIGS. 1 and 5 ; and 
         FIG. 7  illustrates a block diagram of an embodiment of elements of  FIG. 5  and various possible interconnections between these elements. 
     
    
    
     DETAILED DESCRIPTION 
     Systems and methods are provided for processing group membership data in a multitenant database system. As used herein, the term multi-tenant database system (MTS) refers to those systems in which various elements of hardware and software of the database system may be shared by one or more users. 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. 
       FIG. 1  illustrates a database architecture  5  employing virtual portals  6 ,  7  and  8  in an MTS architecture that affords access to a database  9  having tenant information  10  and  11 , associated with a tenant, by multiple users  12 - 14  over a data communication network  16 . Architecture  5  includes information corresponding to more than one tenant, with the understanding that a tenant is an organization that obtains rights to store information on database  9  and make the same accessible to one or more users  12 - 14  to whom tenant provides authorization. This is typically achieved by rental agreements between the tenant and an owner/provider of architecture  5 . In this manner, architecture  5  provides an on-demand database service to users  12 - 14  that are not necessarily concerned with building and/or maintaining the database system; rather, these functions are addressed between the tenant and the owner/provider. Tenant information  10  and  11  may include software applications, application data, and the like. Although information corresponding to two different tenants is shown, in practice information corresponding to any number of tenants may be present. 
     Each virtual portal  6 ,  7  and  8  provides an “instance” of a portal user interface, coupled to allow access to database  9 . With architecture  5 , multiple users  12 - 14  may access information on database  9  through a common network address, in this example a universal resource locator (URL). In response, web-pages and other content may be provided to users  12 - 14  over network  16 . The resources of database  9  that users  12 - 14  may access can be different, depending on user&#39;s  12 - 14  security or permission level and/or tenant association. For example, in some MTSs, tenants may be allowed to provide users  12 - 14  associated with the tenant, referred to as tenant users, access to a sub-portion of the content of the database information that the tenant may be allowed to access. The sub-portion that anyone of the tenant users may access may be the same as or different from the sub-portion that the remaining tenant users may access. User&#39;s not associated with a tenant would not be allowed access to the tenant information. For example, assume users  12  and  13  are associated with the tenant corresponding to tenant information  10  and not associated with the tenant corresponding to tenant information  11 . Users  12  and  13  would not be allowed access to tenant information  11  and would be allowed access to tenant information  10  or a sub-portion thereof. In the present example user may be allowed access to a portion  15  of tenant information  10  and user  13  may be allowed access to a portion  19  of tenant information  10 , which is mutually exclusive. Similarly, were user  14  associated with the tenant corresponding to tenant information  11  and not the tenant corresponding to tenant information  10 , user  14  would be allowed to access tenant information  11 , or a portion thereof, and not tenant information  10 . It is possible, however, that one of users  12 - 14  are associated to the tenants corresponding to both sets of tenant information  10  and  11 . As a result, a tenant may be considered a group having one or more users  12 - 14  associated therewith. 
     Data communication network  16  may be any network or combination of networks of devices that communicate with one another. For example, network  16  can be anyone 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 present invention might use are not so limited, although TCP/IP is a frequently implemented protocol. As a result, users  12 - 14  may access the corresponding tenant information  10  and  11  from any location where network access is available. 
     To this end, virtual portals  6 ,  7  and  8  facilitates providing resources of database  9  that a tenant may provide to users  12 - 14  associated with the tenant. Each user  12 - 14  logs into one of virtual portals  6 ,  7  and  8  to access resources of database  9  through a unique uniform resource locator (URL) or other type of address. Based on the URL and other identifying information associated with users  12 - 14 , architecture  5  may determine the resources of database  9  users  12 - 14  may access. For example, user  12  communicates with database through virtual portal  6 , user  13  communicates with database  9  through virtual portal  7 , and user  14  communicates with database through virtual portal  8 . It is possible, however, that all users  12 - 14  may use a common portal, as well. To that end, users desiring to access resources of database  9  employ virtual portals  6 ,  7  and  8  to validate against the information stored on system  5 , corresponding to the user  12 - 14  requesting access to a sub-portion of content on database  9 . 
     An example of a tenant may be a company that employs a sales force where each salesperson uses server system  30  to manage their sales process, such as by a management representative of the tenant, e.g., Vice President of Sales, the Chief Executive Officer of the tenant and the like. In this fashion, architecture facilitates Customer Relations Management (CRM). Thus, one or more of users  12 - 14  may be a salesperson that maintains information that is applicable to that salesperson&#39;s sales process and is different from information related to other salespersons&#39; sales process. An example of sales process data may include, without limitation, contact data, leads data, customer follow-up data, performance data, goals and progress data applicable to that salesperson&#39;s personal sales process. The sales process information may be stored in database  9 . To facilitate management of this information, the tenant associated with the salesperson may restrict each salesperson access to specific sales process information. However, a tenant, or representative thereof based upon a contractual relation ship between the salesperson and the representative, may be able to view all sale process information for the salespersons associated with the tenant. An example of a contractual relationship is a managerial/supervisory relationship. The managerial relationship between the salesperson and the tenant representative may provide the representative with a higher permission level when compared to the permission level of the salesperson, because, inter alia, the tenant representative may be a manager/supervisor of the salesperson. Another contractual relationship may be the principle agent relationship wherein the tenant representative has no day-to-day management responsibility of the salesperson. Nonetheless, as the representative of the principle, e.g., the tenant, the representative may view all of the salesperson information, because the salespersons may be deemed to be merely agents of the tenant. 
     This is referred to as a hierarchical data structure in which users at one permission level, in this example the representative, may have access to applications, data, and database information accessible by a lower permission level user, in this example the salespersons, with the salesperson not having access to certain applications, database information, and data accessible by a user at a higher permission level, the representative. In this fashion, the representative may access all information that the tenants&#39; user could access, in this example, salespersons; however, the tenant&#39;s user, in the present example a salesperson, is not necessarily allowed to access information of the representative. As a result, the representative is a sub-group of the tenant group. Similarly, an administrator of the architecture  5  may access and control all information available to each of the tenants, as well as the tenant users associated with each tenant. It is conceivable that other sub-groups may exist. 
     Referring to  FIG. 2 , for example, a number of salespersons may be located in a geographic location which may be considered a geographic sub-group, which is shown as sub-groups  20  and  21 . Sub-group  20  includes users  12  and  13 , and sub-group  21  includes user  14 . A representative of tenant, user  23 , may have a managerial relationship with respect to users  12  and  13  by virtue of the association with sub-group  20 , i.e., user may be the Vice-President of Sales for the geographic region corresponding to sub-group  20 . Similarly, a representative of tenant, user  24 , has a managerial relationship with respect to user  14  by virtue of the association with sub-group  21 , i.e., user may be the Vice-President of Sales for the geographic region corresponding to sub-group  21 . In addition, it may be seen that an additional user  25  has a managerial relationship with respect to users  23  and  24 . As a result of the relation of user  25  to users  23  and  24 , users  23  and  24  may be viewed as an additional sub-group  26  of the tenant. Thus, there exists an access authorization relationship (AAR) among sub-groups  26  and  20  and  21  such that any user having access to sub-group  26  also has access to both sub-groups  20  and  21 . The AAR exists independent of the users associated with sub-groups  26 ,  20  and  21 . However, the association of any given user with a managerial relationship is transitive in nature. The transitive nature of a user with a managerial relationship is a natural consequence of the business environment in which an individual user may change occupations within a given tenant and/or may become dissociated from a tenant. As a result, the individual user&#39;s right to access information based upon the managerial association may change. 
     Referring to  FIGS. 1, 2 and 3 , in operation relational database management system (RDMS) or the equivalent may execute storage and retrieval of information against the database object(s). At step  200  a request is received from a user/tenant representative, such as  12 - 14  and  20 - 21  and  25 , respectively, to access a portion of the content on database  9 . The request includes identification information that is unique to the requesting user/tenant representative. In the present example, requests for access to content on database  9  is processed as a query during which database  9  determines groups of users associated with the portion of the content of database for which access is requested, at step  202 . The portion of the content of database  9  is referred to as an account. This is achieved employing associational data registry (ADR)  17  that includes a data set  18  associating groups, such as groups  20 ,  21  and  26  with the account. Following a determination of the groups associated with the account, the users associated with the groups are determined at step  204 . Upon determining the users associated with the groups database  9  compares the identification of a user that provided the query with the users associated with the group to determine whether access should be granted at step  206 . For example, assuming that users  12  and  13  are associated with a tenant corresponding to tenant information  10  and user  14  is associated with the tenant corresponding to tenant information  11 . Requests for access to database  9  would be transmitted via virtual portals  6  and  7 , respectively. In response to the request a sub-portion of tenant information  10 , which is the subject of the request, is transmitted to users  12  and  13 . Were it determined that the resources and content to be provided to users  12 - 14  was improper, in one embodiment architecture  5  would merely restrict this information from being made available to users  12 - 14 . The remaining resources and content that is the subject of the request for access would be provided. The tenant and/tenant representative associated with the users  12 - 14  could be made aware that one or more of users  12 - 14  had attempted to access resources of database  9  that users  12 - 14  were not authorized to access. This may be achieved, for example, through owner/provider transmitting an e-mail message, an instant message, and/or a letter to the address of tenant. Of course, notification to the tenant by the owner/provider may be avoided altogether. Alternatively, were it determined that the resources and content to be provided to users  12 - 14  was improper, architecture  5  would restrict any resources of database  9  from being accessed by the users  12 - 14  requesting access, including resources and content that would otherwise be proper for the requesting user  12 - 14  to access. Notification to the tenant of the situation may or may not occur as discussed above. 
     Referring to again  FIG. 1  to improve the operational characteristics of architecture  5  while providing the hierarchical data structure it is advantageous to organize the relationships, between groups and users, amongst multiple tables. This facilitates providing efficient processing of group membership data of the database by easing changes to the group membership and processing of queries to the data by maintaining acceptable number of processing cycles to respond to queries for access. To that end, ADR  17  includes two additional sets  27  and  28  of data. Data set  28  is a normalized data structure and associates individual members with groups. Data set  27  is a data structure in which the information contained therein is substantially independent of user-group association information. It was determined that the managerial relationships between different users of the database resulted in duplicative information being present in any given table. This resulted from having to maintain the AAR defined by managerial relationship and the transitive nature of the users associated with the managerial relationship. However, it is desired to maintain the AAR among the various sub-groups associated with a given tenant. Thus, information related to AAR is maintained in set  27 , as well as information related to whether there exists transitive information with respect to sub-groups identified in set  27 . With this data configuration a complete table concerning which user may access content on the database is obtained as a result of a join operation of sets  27  and  28  which produces a table that includes information concerning all users having access to the sub-portion of content on the database for which access is sought. 
     It should be understood that “table” and “object” may be used interchangeably herein. As a result, tenant information  10  and  11 , as well as ADR  17 , may 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 according to the present invention. 
     Referring to both  FIGS. 2 and 4 , another embodiment of the present invention includes step  300  during which architecture  5  receives, from a user, e.g.,  10  a request to access a sub-portion of the content contained on data base  9 . The request includes requester identification data. At step  302  groups having access to the sub-portion are identified. At step  304 , the members associated with the groups are determined by joining data in sets  27  and  28 . At step  306  a decision is made to determine whether the requester identification data corresponds to the member information. This is premised upon determining whether the user requesting access to the sub-portion is included in the users identified in step  304 . If yes, then step  308  occurs during which the sub-portion is sent to the requester. If not, then step  310  occurs in which a denied access message is sent to the requester. 
     Referring to  FIGS. 1, 5 and 6  a block diagram of a server system  30  employed to implement architecture  5  is shown as including multiple user systems  32  in data communication with server system  30  over network  16 . Server system  30  includes a processor system  36 , application platform  38 , network interface  40 , and database  9 , which includes tenant data storage  42 , system data storage  44 . In addition server system  30  includes program code  46 , and process space  48 . Program code  46  may include, among other code, code to facilitate a tenant to control the look-and-feel of the experience users  12 - 14  have when accessing database  9 . Process space  48  facilitates execution of MTS system processes and tenant-specific processes, such as running applications as part of an application hosting service. Additional processes that may execute on server system  30  include database indexing processes. In other embodiments, server system  30  may not have all of the components listed and/or may have other elements instead of, or in addition to, those listed above. Server system  30 , and additional instances of an MTS, where more than one is present, and all components thereof may be operator configurable using applications including computer code to run using a central processing unit such as processor system  36 , which may include an Intel Pentium® processor or the like, and/or multiple processor units. 
     Application platform  38  may be a framework that allows the applications of architecture  5  to run, such as the hardware and/or software, e.g., the operating system. In an embodiment, application platform  38  may enable creation, managing and executing one or more applications developed by the owner/provider of architecture  5 , users  12 - 14  accessing architecture  5  via user systems  32 , or third party application developers accessing architecture  5  via user systems  32 . 
     In one embodiment, server system  30  implements a web-based customer relationship management (CRM) system. For example, in one embodiment, server system  30  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  32  and to store to, and retrieve from, database system related data, objects, and Webpage content. Architecture  5  typically stores data for multiple tenants 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, server system  30  implements applications other than, or in addition to, the CRM application discussed above. For example, server system  30  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  38 , 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 server system  30 . 
     To facilitate web-based CRM, user systems  32  might communicate with server system  30  using TCP/IP and, at a higher network level, use other common Internet protocols to communicate, such as HTTP, FTP, AFS, WAP, etc. To that end, user systems  32  may be any computing device capable of interfacing directly or indirectly to the Internet or other network connection, such as desktop personal computer, workstation, laptop, PDA, cell phone, or any wireless access protocol (WAP) enabled device and the like running an HTTP client  49 . An example of a user system  32  includes a processor system  50 , a memory system  52 , an input system  54 , and output system  56 . Processor system  50  may be any combination of one or more processors. Memory system  52  may be any combination of one or more memory devices, volatile, and/or non-volatile memory. A portion of memory system is used to run operating system  58  in which HTTP client  49  executes. Input system  54  may be any combination of input devices, such as one or more keyboards, mice, trackballs, scanners, cameras, and/or interfaces to networks. Output system  56  may be any combination of output devices, such as one or more monitors, printers, and/or interfaces to networks. HTTP client  49  allows users  12 - 14  of users systems  32  to access, process and view information, pages and applications available to it from server system  30  over network  16 . Examples of HTTP client  49  include various browsing applications, such as Microsoft&#39;s Internet Explorer browser, Netscape&#39;s Navigator browser, Opera&#39;s browser, or a WAP-enabled browser in the case of a cell phone, PDA or other wireless device, or the like. Access is gained to requisite tenant information  10  and  11  by entering the URL (not shown) into the URL box  60  of HTTP client  49 . The URL directs users  12 - 14  to the appropriate virtual portal for to determine authorization and permission level to access the requisite tenant information. 
     Data corresponding with each user  12 - 14  may be separate from the data corresponding to the remaining users  12 - 14  regardless of the tenant associated with users  12 - 14 ; however, some data might be shared or accessible by a plurality of users  12 - 14  or all of users  12 - 14  associated with a tenant. Thus, there might be some data structures managed by server system  30  that are allocated at the tenant level while other data structures might be managed at the user level. Because an MTS typically 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, server system  30  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. 
     According to one embodiment, server system  30  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. 
     Referring to  FIG. 7 , a specific embodiment of a server system  30  may include tenant data storage  42  and system data storage  44 , which are as discussed above. In addition, server system  130  includes a user interface (UI)  70 , application program interface (API)  72 , PL/SOQL  74 , save routines  76 , an application setup mechanism  78 , applications servers  80   1 - 80   N , system process space  82 , tenant process spaces  84 , tenant management process space  86 , tenant information  88 , user storage  90 , and application metadata  92 . In other embodiments, server system  30  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. Network interface is implemented as a plurality of HTTP application servers  80   1 - 80   N . Also shown is system process space  82 , including individual tenant process spaces  84  and a tenant management process space  86 . 
     Referring to  FIGS. 1, 5 and 7 , each application server  80   1 - 80   N  may be configured to service requests of user systems  32  for access to tenant data storage  42  and the tenant information  10 , as well as data system storage  44 . Tenant information  10  consists of different information storage areas that may physical differentiation, e.g., different hard disks, and/or a logical separation of the information. Within each tenant storage area  42 , information may be included therein that consists of user storage  90  and application metadata  92  for each user or a groups of users. For example, a copy of a user&#39;s most recently used (MRU) items might be stored to user storage  90 . Similarly, a copy of MRU items for an entire organization that is a tenant might be stored to an area of tenant data storage  42 . UI  70  provides a user interface and API  72  provides an application programmer interface to server system  30  resident processes to users and/or developers at user systems  32 . The tenant data and the system data may be stored in various databases, such as one or more Oracle™ databases. 
     Referring again to  FIGS. 1, 5 and 7 , it is not necessary that the one or more HTTP application servers  80   1 - 80   N  be implemented as the sole network interface between server system  30  and network  16 . Rather, other communication techniques might be used in conjunction with HTTP application servers  80   1 - 80   N  or in lieu thereof In some implementations, the interface between server system  30  and network  16  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 users  12 - 14  one of HTTP application servers  80   1 - 80   N , each of the plurality of servers has access to the MTS data; however, other alternative configurations may be used instead. 
     Application platform  38  includes an application setup mechanism  78  that supports application developers&#39; creation and management of applications, which may be saved as metadata  92  by save routines  76  for execution by subscribers as one or more tenant process spaces  84  managed by tenant management process  86 , for example. Invocations to such applications may be coded using PL/SOQL  74  that provides a programming language style interface extension to API  72 . A detailed description of some PL/SOQL language embodiments is discussed in commonly owned co-pending U.S. patent application Ser. No. 11/859,498 entitled, METHOD AND SYSTEM FOR ALLOWING ACCESS TO DEVELOPED APPLICATIONS VIA A MULTI-TENANT ON-DEMAND DATABASE SERVICE, by Craig Weissman, filed Sep. 21, 2007, which is incorporated in its entirety herein for all purposes. Invocations to applications may be detected by one or more system processes, which manage retrieving application metadata  92  for the subscriber making the invocation and executing the metadata as an application in a virtual machine. 
     Each HTTP application servers  80   1 - 80   N  may be communicably coupled to database systems, e.g., having access to system data  34  and tenant data  32 , via a different network connection. For example, one HTTP application server  80   1  might be coupled via the network  16  (e.g., the Internet), another HTTP application servers  80   1 - 80   N  might be coupled via a direct network link, and another one of HTTP application servers  80   1 - 80   N  might be coupled by yet a different network connection. Transfer Control Protocol and Internet Protocol (TCP/IP) are typical protocols for communicating between HTTP application servers  80   1 - 80   N  and database  9 . 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. 
     In certain embodiments, each of HTTP application servers  80   1 - 80   N  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 one of HTTP application servers  80   1 - 80   N . In one embodiment, therefore, an interface system implementing a load balancing function (e.g., an F 5 Big-IP load balancer) is communicably coupled between HTTP application servers  80   1 - 80   N  and the user systems  32  to distribute requests to HTTP application servers  80   1 - 80   N . In one embodiment, the load balancer uses a least connections algorithm to route user requests to HTTP application servers  80   1 - 80   N . 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  12 - 14  could hit three different HTTP application servers  80   1 - 80   N , and three requests from different user systems  32  could hit a common HTTP application server  80   1 - 80   N . In this manner, server system  30  is multi-tenant, wherein server system  30  handles storage of, and access to, different objects, data and applications across disparate users and organizations. 
     In certain embodiments, user systems  32  (which may be client systems) communicate with HTTP application servers  80   1 - 80   N  to request and update system-level and tenant-level data from server system  30  that may require sending one or more queries to tenant data storage  42  and/or system data storage  44 . Server system  30  (e.g., an application server  80  in server system  30 ) 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  44  may generate query plans to access the requested data from the database. 
     While the invention has been described by way of example and in terms of the specific embodiments, it is to be understood that the invention is 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. For example, the present processes may be embodied as a computer program product that 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 the server system 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 of the present invention 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.). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.