Abstract:
A structured query language interface provides access to information stored in a social network system. The interface allows third party systems to treat the information stored in the social networking system as a distributed database. The social networking system acts as an expandable distributed database that can add additional fields or categories of data associated with its members. The information provided in response to a structured query may be subject to multiple levels of access control including, business logic rules applicable to users of the social networking system or privacy limitations set by individual users. The social networking system uses a scripting language to extract the information and apply business logic rules to the data.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims the benefit and priority of U.S. Provisional Patent Application Ser. No. 60/902,777 filed on Feb. 21, 2007, titled “Systems and Methods for Implementation of a Structured Query Language Interface in a Distributed Database Environment,” which is hereby incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to web applications that provide an Application Program Interface (“API”) for external, untrusted developers and more particularly to systems and methods for implementation of a structured query language interface in a distributed database environment. 
     2. Description of Related Art 
     Conventionally, Structured Query Language (“SQL”) is designed for querying data contained in a single relational database. Though widely understood and adopted, SQL is not designed for querying data contained in a distributed database, nor is it designed for providing access to this data to external developers. Instead, alternative Application Program Interfaces are used by external developers to access this data. 
     Alternative Application Program Interfaces suffer from several drawbacks. First, most alternative Application Program Interfaces are incapable of performing focused queries. Thus, bandwidth and computing resources are wasted in providing query responses that may contain large amounts of irrelevant data. Second, third-party developers employing alternative Application Program Interfaces typically need to reconfigure their respective programs for each new query routine. Accordingly, when a distributed database is expanded with one or more additional categories of data, third-party developers generally need to spend time reconfiguring their respective programs. Third, business logic rules imposed by an administrator and/or a user of a distributed database typically must be applied to data to be queried via an alternative Applied Program Interface before third-party developers may access the data. Thus, there is a need for systems and methods for implementation of a structured query language interface in a distributed database environment. 
     SUMMARY OF THE INVENTION 
     Systems and methods for implementation of a structured query language interface in a distributed database environment are provided. Exemplary systems include a distributed database configured with items of data, a volatile cache memory configured with a subset of the items of data, a scripting language configured to extract data from the volatile cache memory, and a structured query language interface configured to receive a query over a network, to send the query to the scripting language, and to receive extracted data from the scripting language in response to the query. Further systems include the scripting language configured to apply business logic rules to the extracted data before the extracted data is sent to the structured query language interface. The structured query language interface may also be further configured to send some or all of the extracted data in a format to accommodate a database maintained by a third-party developer. 
     Exemplary methods include configuring a distributed database with items of data, configuring a volatile cache memory with a subset of the items of data, configuring a scripting language to extract data from the volatile cache memory, and configuring the structured query language interface in communication with the scripting language to receive a query over a network, to send the query to the scripting language, and to receive extracted data from the scripting language in response to the query. Further methods include configuring the scripting language to apply business logic rules to extracted data before the extracted data is sent to the structured query language interface. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates an exemplary architecture according to one system and method for implementation of a structured query language interface in a distributed database environment; 
         FIG. 2  shows an exemplary reference table for conducting SQL queries via a third-party developer SQL interface; 
         FIG. 3  is a flow chart of an exemplary method for implementation of a structured query language interface in a distributed database environment; and 
         FIG. 4  is a flow chart of an exemplary method for performing a query of a distributed database. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     According to various exemplary systems and methods, an SQL interface is used by one or more third-party developers to query an expandable distributed database. Query responses may be subject to business logic rules imposed by an administrator and/or user of the distributed database. As additional categories of information are added to the distributed database, third-party developers may source the information found in the additional categories, without having to reconfigure their respective systems. Because query constraints may include such commands as the WHERE clause and only list certain fields in the SELECT clause, query responses match a specific condition, rather than providing all of the information available about a large set of items. 
       FIG. 1  illustrates an exemplary architecture according to one system and method for implementation of a structured query language interface in a distributed database environment. The exemplary architecture  100  may include an SQL interface  105 , a network  110 , a third-party developer  115 , a scripting language  120 , optional business logic rules  125 , a volatile cache memory  130 , and a distributed database  135 . The network  110  may represent any network where the transmission of digital content occurs, including the Internet. The third-party developer  115  may be a software developer or any other party with a networked application or web site that may also be a separate entity from the entity responsible for the underlying or primary software being used, such as a web-based social network. For example, the third-party developer  115  may provide an external software tool that helps organize or use the information within the social network. 
     According to various exemplary systems, the distributed database  135  may represent a distributed database for a web-based social network. The distributed database  135  may be comprised of multiple databases and the number of databases may increase or decrease over time. 
     The volatile cache memory  130 , in one exemplary system and method, may pool most or all of the data found in the distributed database  135 . In general, the volatile cache memory  130  facilitates rapid query response times, when compared to the time required for querying all or most all of the databases forming the distributed database  135 . Further, the data found in the volatile cache memory  130  may represent the data set from which a particular query response may be sourced. The data found in the distributed database  135  may represent the data sourced in a query response if the volatile cache memory  130  appears to lack certain pieces of data that may be the subject of a particular query and found in the distributed database  135 . 
     In one further exemplary system and method, the optional business logic rules  125  may represent limitations selected by the users or members of a web-based social network. For example, a member of the social network may limit the other members of the social network that may access the member&#39;s personal information, such as the member&#39;s address and telephone number. The business logic rules  125  may also represent limitations selected by an administrator of the social network. 
     The scripting language  120 , according to various exemplary systems, may be any programming environment typically used to create dynamic web pages, including, however not limited to, PHP Hypertext Preprocessor. With syntax from C, Java and Perl, PHP code may be embedded within HTML pages for server side execution. PHP may be used to extract data from a database in order to present it on a web page. PHP may extract data out of the volatile cache memory  130 . Optionally, PHP may apply the business logic rules  125  against extracted data. It is this data (with or without application of the business logic rules  125 ) that is generally provided to the third-party developer  115  in the form of an SQL query response. 
     In one exemplary system, the SQL interface  105  may utilize SQL-style syntax for queries. For example, the third-party developer  115 , such as an online book retailer, may wish to learn the identities of the members of a web-based social network who have an interest in baseball. Accordingly, the third-party developer  115  may utilize the SQL interface  105  to perform such a query. Optionally, a response provided to the third-party developer  115  utilizing the SQL interface  105  may be limited by the business logic rules  125 , such as privacy limitations. For example, the third-party developer  115  may receive the name, however, not the email address of a particular social network member who is interested in baseball. 
     According to further exemplary systems and methods, query responses provided to a third-party developer, such as the third-party developer  115 , are automatically formatted to accommodate the database of the third-party developer. For example, numerous third-party developers may each have a database, with each database having various subsets of the data found in an expandable distributed database, such as the distributed database  135 . An expandable distributed database may be represented by a social network that adds additional fields or categories of data associated with its members. For instance, a social network may add a field to its distributed database for the brand of car owned by each of its members. Accordingly, some third-party developers may wish to modify their respective databases to include this new information, subject to any business logic rules (e.g. business logic rules  125 ) imposed by the social network and/or its members. The responses provided to the third-party developers are automatically formatted to accommodate the respective databases of the third-party developers. 
       FIG. 2  shows an exemplary reference table for conducting SQL queries via a third-party developer SQL interface. The exemplary reference table  200  includes a left column having the heading of “Table” that corresponds to strings that may be used in the FROM clause, while the right column having the heading of “Columns” corresponds to columns that may be referenced in the SELECT and WHERE clauses. 
     Based on one exemplary system and method, queries may be indexable. In order to make a query indexable, the WHERE may contain an “=” or “IN” clause for one of the columns marked with a “*”. A third-party developer may not, for example, just specify WHERE 1 as the entire WHERE clause, since in many cases this may result in far too large of a result set (the photos table as described herein, for example, may contain over 1 billion entries). In general, queries should be limited to working on a specific, enumerable set of items, by referencing one of the indexable columns (i.e. the columns marked with a “*” in reference table  200 ) in the WHERE clause. More specifically, if the WHERE clause were to be written in Disjunctive Normal Form, each conjunction should contain at least one “=” or “IN” expression that uses an indexable column. 
     Queries, according to various exemplary methods, may be in the form SELECT [fields] FROM [table] WHERE [conditions]. The FROM clause in the third-party developer SQL interface may contain only a single table. Additionally, in the SELECT or WHERE clauses, the IN keyword may be used to perform subqueries, but the subqueries may not reference variables in the outer query&#39;s scope. 
     For example, using the exemplary reference table  200  shown in  FIG. 2 , a third-party developer, such as the third-party developer  115  ( FIG. 1 ), may wish to obtain the names and networks for the friends of a particular social network member who works at a company called “Facebook.” Accordingly, the third-party developer may utilize the third-party developer SQL interface to query:
         SELECT name, affiliations FROM user   WHERE uid IN (SELECT uid2 FROM friend WHERE uid1=211031) AND “Facebook” IN affiliations.name.       

     In response, the third-party developer may be provided with the following information: 
     
       
         
               
               
             
           
               
                   
                   
               
             
             
               
                   
                   &lt;?xml version=“1.0” encoding=“UTF-8”?&gt; 
               
               
                   
                   &lt;fql_query_response xmlns=“http://api.facebook.com/1.0/” 
               
               
                   
                 xmlns:xsi=“http://www.w3.org/2001/XMLSchema-instance” 
               
               
                   
                 xsi:schemaLocation=“http://api.facebook.com/1.0/ 
               
               
                   
                 http://api.facebook.com/1.0/facebook.xsd” list=“true”&gt; 
               
               
                   
                   &lt;user&gt; 
               
               
                   
                   &lt;name&gt;Mark Zuckerberg&lt;/name&gt; 
               
               
                   
                   &lt;affiliations list=“true”&gt; 
               
               
                   
                   &lt;affiliation&gt; 
               
               
                   
                   &lt;nid&gt;50431648&lt;/nid&gt; 
               
               
                   
                   &lt;name&gt;Facebook&lt;/name&gt; 
               
               
                   
                   &lt;type&gt;work&lt;/type&gt; 
               
               
                   
                   &lt;status/&gt; 
               
               
                   
                   &lt;year/&gt; 
               
               
                   
                   &lt;/affiliation&gt; 
               
               
                   
                   &lt;affiliation&gt; 
               
               
                   
                   &lt;nid&gt;16777217&lt;/nid&gt; 
               
               
                   
                   &lt;name&gt;Harvard&lt;/name&gt; 
               
               
                   
                   &lt;type&gt;college&lt;/type&gt; 
               
               
                   
                   &lt;status&gt;Undergrad&lt;/status&gt; 
               
               
                   
                   &lt;year/&gt; 
               
               
                   
                   &lt;/affiliation&gt; 
               
               
                   
                   etc... 
               
               
                   
                   
               
             
          
         
       
     
     As another example, using the exemplary reference table  200 , a third-party developer may wish to obtain the photo image sources and captions for photos in which two given users or members of the social network are both tagged, and only for those photos in the set that have captions. Accordingly, the third-party developer may utilize the third-party developer SQL interface to query:
         SELECT src, caption FROM photo   WHERE pid IN (SELECT pid FROM photo_tag WHERE subject=211031) AND   pid IN (SELECT pid FROM photo_tag WHERE subject=204686) AND caption.       

     In response, the third-party developer may be provided with the following information: 
     
       
         
               
               
             
           
               
                   
                   
               
             
             
               
                   
                   &lt;?xml version=“1.0” encoding=“UTF-8”?&gt; 
               
               
                   
                   &lt;fql_query_response xmlns=“http://api.facebook.com/1.0/” 
               
               
                   
                 xmlns:xsi=“http://www.w3.org/2001/XMLSchema-instance” 
               
               
                   
                 xsi:schemaLocation=“http://api.facebook.com/1.0/ 
               
               
                   
                 http://api.facebook.com/1.0/facebook.xsd” list=“true”&gt; 
               
               
                   
                   &lt;photo&gt; 
               
               
                   
                   &lt;src&gt;http://photos- 
               
               
                   
                 923.ak.facebook.com/ip002/v61/188/75/206412/ 
               
               
                   
                 s206412_31508923_7923.jpg&lt;/src&gt; 
               
               
                   
                   &lt;caption&gt;celebrating 23 years of ari&#39;s life at the one and the 
               
               
                   
                 oasis.&lt;/caption&gt; 
               
               
                   
                   &lt;/photo&gt; 
               
               
                   
                   &lt;photo&gt; 
               
               
                   
                   &lt;src&gt;http://photos- 
               
               
                   
                 447.ak.facebook.com/ip005/v40/164/17/202965/ 
               
               
                   
                 s202965_30849447_4635.jpg&lt;/src&gt; 
               
               
                   
                   &lt;caption&gt;Liar&#39;s Dice...&lt;/caption&gt; 
               
               
                   
                   &lt;/photo&gt; 
               
               
                   
                   &lt;photo&gt; 
               
               
                   
                   &lt;src&gt;http://photos- 
               
               
                   
                 480.ak.facebook.com/ip005/v29/188/75/206412/ 
               
               
                   
                 s206412_30452480_140.jpg&lt;/src&gt; 
               
               
                   
                   &lt;caption&gt;the crew. (RishDAWG!)&lt;/caption&gt; 
               
               
                   
                   &lt;/photo&gt; 
               
               
                   
                   &lt;photo&gt; 
               
               
                   
                   &lt;src&gt;http://photos- 
               
               
                   
                 103.ak.facebook.com/ip001/v12/188/75/206412/ 
               
               
                   
                 s206412_30325103_6676.jpg&lt;/src&gt; 
               
               
                   
                   &lt;caption&gt;group photo!!!!&lt;/caption&gt; 
               
               
                   
                   &lt;/photo&gt; 
               
               
                   
                   &lt;photo&gt; 
               
               
                   
                   &lt;src&gt;http://photos- 
               
               
                   
                 399.ak.facebook.com/ip001/v10/188/75/206412/ 
               
               
                   
                 s206412_30191399_9134.jpg&lt;/src&gt; 
               
               
                   
                   &lt;caption&gt;someone is particularly happy to be in this 
               
               
                   
                   picture&lt;/caption&gt; 
               
               
                   
                   &lt;/photo&gt; 
               
               
                   
                   &lt;photo&gt; 
               
               
                   
                   &lt;src&gt;http://photos- 
               
               
                   
                 716.ak.facebook.com/ip007/v16/129/99/204686/ 
               
               
                   
                 s204686_30190716_7256.jpg&lt;/src&gt; 
               
               
                   
                   &lt;caption&gt;One of the most extravagant.&lt;/caption&gt; 
               
               
                   
                   &lt;/photo&gt; 
               
               
                   
                   &lt;/fql_query_response&gt; 
               
               
                   
                   
               
             
          
         
       
     
       FIG. 3  is a flow chart of an exemplary method for implementation of a structured query language interface in a distributed database environment. 
     At step  310 , a distributed database is configured with items of data. According to one exemplary method, the distributed database is associated with a web-based social network. 
     At step  320 , a volatile cache memory is configured with a subset of the items of data in the distributed database. 
     At step  330 , a scripting language is configured to extract data from the volatile cache memory. 
     At step  340 , a structured query language interface is configured to receive a query over a network, to send the query to the scripting language, and to receive extracted data from the scripting language in response to the query. 
     At step  350 , the structured query language interface is configured to send some or all of the extracted data to a third-party developer in a format to accommodate a database maintained by the third-party developer. 
       FIG. 4  is a flow chart of an exemplary method for performing a query of a distributed database. 
     At step  410 , a query is received over a network from an application or web site maintained by a third-party developer. 
     At step  420 , data responsive to the query is extracted by a structured query language. 
     At step  430 , business logic rules are applied to the extracted data. 
     At step  440 , the extracted data is formatted to accommodate a database maintained by the third-party developer. 
     At step  450 , the formatted extracted data is sent over the network to the third-party developer. 
     While various systems and methods have been described above, it should be understood that they have been presented by way of example only, and not limitation.