Patent Application
20240256547
The present disclosure relates to database management, and, more specifically, to controlling processing of database queries.
Query languages are used to extract information from databases and information systems. Using a query language, such as the Structured Query Language (SQL), users can retrieve, manipulate, and transform data in relational databases. A relational database is a collection of related tables with a fixed number of named columns and any number of rows of data. Queries are textual statements requesting retrieval of a particular set of data from relational databases.
Database management involves controlling access of information in databases by queries to maintain security, performance, and other operational parameters. Some access control techniques place few, if any, restrictions on queries. However, the techniques may only offer administrators high level control over the information accessed by the queries. For example, access control policies may restrict users' connection to particular databases and information users can access. Some other access control techniques give administrators full control over queries made to databases, but allow little or no flexibility for users to construct queries tailored to the users' individual purposes. Also, the techniques typically implement restrictions on case-by-case bases. As a result, the techniques can be costly and time consuming to develop and maintain.
The approaches described in this Background section are ones that could be pursued, but not necessarily approaches that have been previously conceived or pursued. Unless otherwise indicated, it should not be assumed that any of the approaches described in this section qualify as prior art.
Embodiments are illustrated by way of example and not by way of limitation in the figures of the accompanying drawings. In the drawings:
In the following description, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding. One or more embodiments may be practiced without these specific details. Features described in one embodiment may be combined with features described in a different embodiment. In some examples, well-known structures and devices are described with reference to a block diagram form in order to avoid unnecessarily obscuring the present invention.
The embodiments are illustrated by way of example and not by way of limitation in the figures of the accompanying drawings. It should be noted that references to “an” or “one” embodiment in this disclosure are not necessarily to the same embodiment, and they mean at least one.
This Detailed Description section includes the following subsections:
One or more embodiments implement fine-grained control for the execution of queries. The system receives and stores access control rules to be applied to queries. The access control rules may include user-defined rules that are different from and in addition to a set of validation rules. The system applies the access control rules to a received query to determine one or more actions corresponding to the received query. Based on the access control rules, the system may, for example, allow execution of the query without conditions, allow execution of the query under a limiting set of conditions (e.g., time or resource limits), or prevent execution of the query. Furthermore, the system may present warnings and/or information in relation to the received query. The system may reject a request to execute a query, which is otherwise valid (e.g., authorized for a requesting user and executable on a database), based on the application of stored rules to the query.
While this General Overview subsection describes various example embodiments, it should be understood that one or more embodiments described in this Specification or recited in the claims may not be included in this subsection.
The database system 120 can be a system that stores and maintains one or more databases. The database system 120 can comprise one or more hard disk drives, flash drives, or the like. The database can be any type of database, such as a hierarchical database, network database, or a relational database, such as an SQL database.
The administrator device 105 and the user device 107 can be one or more client computing devices allowing users to access and interact with the server 115 and/or the database system 120. For example, the administrator device 105 and the user device 107 can be personal computers, workstations, servers, mobile devices, mobile phones, tablet devices, and/or other processing devices capable of implementing and/or executing server processes, software, applications, etc. The administrator device 105 and the user device 107 can include one or more processors that execute software or other computer-readable instructions and may include a memory to store the software, other computer-readable instructions, and data. The administrator device 105 and the user device 107 can also include a communication device to communicate with the server 115 and the database system 120 via the communication links 117. Additionally, the administrator device 105 and the user device 107 can generate a computer-user interface enabling a user to interact with the server 115 and the database system 120 using input/output devices. For example, by way of the computer-user interface, a user of the user device 107 can connect to the database system 120 via the server 115 to code and submit a query 151 for accessing data, such as tables and records, maintained by the database system 120.
The server 115 can be one or more computing devices that manage communication, access, and operations among the administrator device 105, the user device 107, and the database system 120. One or more embodiments of the server 115 include a validation library 125, a rule configurator 127, a rules library 129, a query validator 131, a query processor 133, a rules engine 135, and a query executor 137.
The validation library 125 can store validation rules 152 for one or more users or clients of the server 115 and/or the database system 120. The validation rules 152 can specify users that may access the database system 120, circumstances under which the users can access the database system 120, and information in the database system 120 the users are authorized to access. For example, the validation rules 152 may restrict access to some or all information stored in the database system 120 based on a users' and/or a clients' authorization, role, competence, authority, obligation, conflict-of-interest, and the like.
The rule configurator 127 can be an application or module for configuring rules 154 for controlling query execution in the database system 120. One or more embodiments can receive inputs from a user of the administrator device 150 including rules 154 for controlling retrieval of information from the database system 120. For example, the rule configurator 127 can receive the rules 154 constructed via inputs to a computer-user interface or via a predefined library recorded on storage device. The rules 154 can be applied based on the content and/or characteristics of a query 151. The rules 154 can comprise criteria and actions. An individual rule can define a mapping between a one or more criteria and one or more actions. The criteria can be based on syntax, semantics, operations, target data, and computing resources of a query 151. Example criteria can include:
Actions can specify one or more operations to perform based on a corresponding query matching a criterion. Actions can function to, for example: prevent execution, limit execution, limit resources consumed, limit results returned, and generate alerts. Example actions can include:
The rule configurator 127 can also generate mappings between one or more criteria and one or more corresponding actions, and store the mapping in the mapping in, for example, the rules library 129. An example rule mapping a criterion to an action can be, for example:
The query validator 131 can be a software application or module that validates database queries, such as the query 151 based on user credentials 159 received from the user device 107 and validation rules 152 stored in the validation library 125. The query validator 131 can determine which, if any, information in the database system 120 a user or client is permitted to and/or prohibited from accessing. For example, the validation library 125 can include information identifying particular tables, rows, or records a user is forbidden to access. In response to determining that the query 151 requests unauthorized information, the query validator 131 can invalidate the query. On the other hand, in response to determining that the query 151 is authorized, the query validator 131 can validate the query 151 and pass the valid query 153 to the query processor 133.
The query processor 133 can be a software application or module that determines content of the query 153, characteristics of the query 153, characteristics of the user requesting the query 153, and characteristics of the database system 120. Content of the query 153 can include operations contained in the query and data requested by the query 153, such as: a quantity and types of joins in the query; a quantity and types of functions in the query; a quantity and types of conditions in the query; a quantity and types of operations in the query; a quantity and types of clauses in the query; a quantity and the types of keywords in the query; a quantity, nested level, and types of sub-queries in the query; a quantity and types of columns used in the query; querying a time series table; and inclusion of time predicates. One or more embodiments of the system determine the contents by parsing the query 153 and creating a parse tree using a query language grammar (e.g., SQL syntax). For example, using a parser, the system can convert the query into a string of elements (e.g., tokens indicating database operations and data), and using a grammar (e.g., grammar 211 below), determine the syntax and semantic patterns of the elements.
The characteristics of the query can include information describing execution of the query 153, including time, resource consumption, result size, and the like. For example, the characteristics can include information from one or more query plans, including instructions for executing the query (e.g., database instructions 163), an estimated resource cost for executing the query (e.g., startup cost and total cost), an amount of information included in the query result (e.g., quantity of rows, average bytes of information per row, and total number of bytes of information). The characteristics of the query 153 can also include query history information such as an average time taken in the past for a particular criterion. Example characteristics of the query 153 can be a number of rows in the target of the query, a number of rows accessed in the target of the query, a number of rows to be returned by the query, an amount of data to be processed for the query, the query causing a full table scan, a query response time for execution of the query, resource usage for execution of the query, and a time for execution of the query.
The characteristics of the user can include usage information and resource consumption by the user. For example, characteristics of the user can include an average time taken for the user's queries, an average size of a results retrieved by the user, and an average amount of computing resources consumed by the user over one or more time frames (e.g., hour, day, month, quarter, or year).
The characteristics of the system can include computing resources currently available or predicted to be available for executing queries. Currently available resources can be determined using characteristics of a current state of the system obtained from a resource management tool. Predicted resources can be determined using historical characteristics of past states of the system from the resource management tool, which can be used to predict a future state of the system. For example, the characteristics can include usage metrics, health metrics, query characteristics, previous query execution plan characteristics, query characteristics of individual users, and available computing resources. Computing resources can include, for example, resources available, resources occupied, quantity of queries currently being executed, and current execution time (e.g., average query execution time or maximum query execution time). For example, the system can determine a number of parallel queries of a particular criterion getting executed at the same time.
The rules engine 135 can be a software application or module that determines whether to reject, execute, or conditionally execute queries by applying the rules 154 stored by the rules library 129 to the query content and characteristics 155 determined by the query processor 133. One or more embodiments of the rules engine 135 apply the rules 154 to the query content and characteristics 155 determined by the query processor 133. For example, the rules library 129 can include a rule specifying that execution of queries including join operations should be rejected. Based on the rules, the rules engine 135 can perform actions defined by the rules. If a rule 154 specifies the validated query 153 should be rejected, then the rules engine 135 can refrain from forwarding the query 153 to the query executor 137 and, instead, communicate a query rejection 157 to the user device indicating the rejection of the query 153, the reasons for the rejection, and any actions taken in association with the rejection, such a locking out the user and alerting administrators. Additionally, some embodiments can communicate the rejection to the administrator device 105. On the other hand, if the rules engine 135 determines the query 153 is authorized without conditions, the rules engine 135 can communicate a query authorization 158 to the query executor 137. Also, if the rules engine 135 determines the query 153 is authorized with conditions, the query authorization 158 can include information specifying the conditions (e.g., a maximum quantity of results and maximum query execution time).
The query executor 137 can be a software application or module that controls the storage, organization, and retrieval of data from database system 120 based on query 153. The query executor 137 can generate database instructions 163 for retrieving database records 165 from the database system 120 to communicate a query result 167 for the user device 107. One or more embodiments of the query executor 137 generate the query instructions 163 including conditions or restrictions in accordance with the rules applied by the rules engine 135. Based on the conditions or restrictions, the query result 167 can be a limited set of records in comparison to a query result 167 generated without conditions or restrictions. For example, based on the restrictions and conditions, the query result 167 can be limited to 1000 records; whereas an unconditional or unrestricted result could include a substantially unlimited quantity of records.
Embodiments of the server 115 can include a processor 203, one or more memory devices 205, and a storage device 209. The processor 203 can be one or more general-purpose processors, special-purpose processors, or other programmable data processing apparatuses providing the functionality and operations detailed herein. The memory device 205 and storage device 209 can be operatively and/or communicatively connected to the processor 203. In some implementations, the memory device 205 and/or the storage device 209 includes one or more types of memory structures. For example, the memory structures can include random access memory (RAMs) units, read only memory (ROMs), flash memory (e.g., solid state drives (SSDs)), electrically erasable/programmable read only memory (EEPROMs), etc. It should be appreciated that communication between the memory device 205, the storage device 209, and the processor 203 or another controller, encompasses the processor or controller accessing the memory device 205 and/or the storage device 209, exchanging data with the memory device 205 and/or the storage device 209 (e.g., reading/writing data to the memory device 205), or storing data to the memory device 205 and/or the storage device 209.
The storage device 209 can store a validation library 125 and rule library 129, which can be the same or similar to those previously described above. The storage device 209 can also store a grammar 211 and resource information 213. The resource information 213 can be a log of information of current and past queries executed on a database (e.g., database system 120). The statistics can include information indicating types of and quantities of queries executed on the database system 120 by the system and by particular users. The statistics can also include information quantifying resources consumed by the queries and results generated by the queries.
The processor 203 can also execute computer-readable program instructions of a rule configurator 127, a query validator 131, a query processor 133, a rule engine 135, and a query executor 137, all of which can be the same or similar to those previously describe above. It is understood that functionality of one or more of the rule configurator 127, the query validator 131, the query processor 133, the rule engine 135, and the query executor 137 can be combined into a common software module and/or divided between additional modules.
It is noted that the server 115 can comprise any general-purpose computing article of manufacture capable of executing computer program instructions installed thereon (e.g., a personal computer, server, etc.). However, the server 115 is only representative of various possible equivalent-computing devices that can perform the processes described herein. To this extent, in embodiments, the functionality provided by the server 115 can be any combination of general and/or specific purpose hardware and/or computer program instructions. In each embodiment, the program instructions and hardware can be created using standard programming and engineering techniques, respectively.
The components illustrated in
The flow diagrams in
Referring to
Configuring the rules can also include, at block 311, mapping one or more actions to the criteria defined at block 307. As previously described above, the actions can include operations controlling the system to reject queries, execute queries, or execute queries with conditions and/or restrictions. The actions can be implemented before, during, or after execution of the queries. For example, actions can include: a time limit for execution of a query, a set of resources that may be accessed by a query, a number of queries that may be concurrently executed with another query, computing resources involved in executing the query, and computing resources available for executing the query. Additionally, one or more embodiments can implement different rules before, during, or after query execution. For example, a first rule can set a time limit (e.g., 10 seconds) before execution of a query, and a second rule can modify the time limit during the execution.
The system can obtain the actions in a same or similar manner as the criteria. Some embodiments can receive a table mapping the criteria with one or more corresponding actions as a table file. Some embodiments can be an interactive graphic user interface for constructing rules, associating the criteria with one or more actions, and checking the rules for syntactic errors. Configuring the rules can also include, at block 315, stores the mapping between the criteria and corresponding actions. For example, the system can store and maintain the mapping in a library (e.g., rules library 129.)
At block 325, the system can receive a query (e.g., query 151) from a user of a user device (e.g., user device 107). For example, a developer can input a query in a user interface of a code editor and submit the query to the system for execution. At block 329, the system (e.g., executing query validator 131) can determine whether the query received at block 325 is valid. One or more embodiments validate the query using one or more access rules (e.g., validation rules 152 stored in the validation library 125) restrict access to some or all information stored in the database system 120. For example, the system can compare user credentials (e.g., credentials 159, such as authorization, role, competence, authority, obligation, and conflict-of-interest) to the access rules. If the query is not valid (e.g., block 327 is “No”), then at block 331 the system can reject the query and, at block 333, present information indicating the rejection of the query via the user device. For example, via a graphic computer-user interface, the system can generate a response to the query indicating that the user is not authorized to execute the query or to access data requested by the query. On the other hand, if the system determines that the received query is valid (e.g., block 327 is “Yes”), then the process 300 proceeds to block 345 on
At block 345, the system (e.g., executing query processor 133) can process the query validated at block 327. Processing the query can include determining content of the query, characteristics of the query, characteristics of the user, and characteristics of the system. Some embodiments receive the request to process the query from the user via the computer-user interface. Other embodiments automatically execute the query based on successful validation at block 327. Processing the query can include, at block 347, determining content of the query, such as the syntax and sematic patterns of the query. For example, using a parser, the system can convert the query into a string of elements (e.g., tokens) and using a grammar (e.g., grammar 211), determine syntax and semantic patterns of the elements.
Processing the query can also include, at block 349, determining characteristics of the query, such as resources involved in executing the query. For example, using a query optimizer, the system can determine one or more query plans for executing the query. The query plan can include an estimated resource cost for executing the query (e.g., startup cost and total cost), an amount of information included in the query result (e.g., quantity of rows, average bytes of information per row, and total number of bytes of information). Query characteristics can also include historical information logged from past queries of the same type. For example, the historical information can include execution time, resource consumption, and result size.
Processing the query can further include, at block 351, determining characteristics of the user requesting the query, such as user history information. User history can include usage information and resource consumption information consumed by queries of the user within one or more time frames. One or more embodiments can maintain a log of each query executed by the user within the last hour, day, week, or the like, along with corresponding quantities of time, computing resources, and data consumed by the queries.
Processing the query can additionally include, at block 353, determining characteristics of the system, such as system resources. Determining system resources can include, for example, resources available, resources occupied, quantity of queries currently being executed, and current execution time (e.g., average query execution time, maximum query execution time). One or more embodiments determine the system resources information based on the received query. For example, the system can determine a number of parallel queries of a particular criterion executed at the same time. The resource information can include current resource availability. Additionally, the resource information can include past resource consumption. For example, the system can retrieve past information of queries including operations and data the same or similar to the query.
At block 355, the system (e.g., executing rules engine 135) can apply one or more of the rules configured at block 305 to the query validated at block 327 based on the contents and characteristics determined at block 345. Applying the rules can include, at block 359, determining whether the query meets one or more of the criteria defined by the rules. If no matching criteria are identified (e.g., block 359 is “No”), the process 300 can proceed to block 387 of
Referring to
For example, if a first action corresponding to a first criterion matching the query indicates the query can be executed, a second action corresponding to a second criterion matching the query indicates the query should be restricted, and a third action corresponding to a third criterion matching the query indicates the query should be rejected, then the most restrictive option would be to reject the query. Accordingly, at block 389, the system can reject the query and proceed to block 377. In another example, if a first action corresponding to a first criterion matching the query indicates the query can be executed, a second action corresponding to a second criterion matching the query indicates the query should be restricted, then the most restrictive option would be to restrict the query. Accordingly, at block 389, the system can restrict the query and proceed to block 377.
At block 377, the system can reject the execution of the query based on the determination at block 389. Rejecting execution can prevent generation or execution of any instructions (e.g., database instructions 163) or retrieving information from the database. Rejecting execution can also prevent consumption of substantially any computing resources of the system or the database that would be involved in executing the query. At block 379, the system can display an indication of the query rejection (e.g., query rejection 157) to the user (e.g., user device 107) via a computer-ser interface (e.g., a user interface). The indication can also include a description of the reasons for the rejection based on the corresponding action.
At block 381, the system can execute the query with each of the restrictions indicated by the actions determined at block 361. As previously described, the restrictions can specify a time limit for execution of the query, a set of resources that may be accessed by the query, and a number of queries that may be concurrently executed with the query, computing resources involved in executing the query, and computing resources available for executing the query. At block 381, the system can retrieve information from the database in accordance with the restrictions identified at block 389. At block 385, the system can present the query results (e.g., query results 167) to the user via the computer-ser interface), along with an indication describing the restrictions imposed on the results. For example, the system can indicate that execution of the query was limited to 30 seconds and 1,000 results.
At block 387, the system can execute the query without restrictions or conditions. At block 389, the system can retrieve information from the database. And, at block 385, the system can present the query results to the user.
Rule 409, “Allow execution for basic queries using basic aggregations,” maps the action “allow query execution” if the query matches criteria 403 and 405. Rule 411, “Force a special time out for queries using joins,” maps the action “set query time out as 30 seconds” if the query matches criterion 407. Rule 413, “Set a special query execution count for queries using joins,” maps the action “allow query execution” if the query matched criterion 403 and the estimated query count will be less than 1000 within 5 minutes. The system can determine the estimated query count and time constraints based on determinations of the characteristics of the query and the current system resources. Rule 415, “Force a result set count to a maximum of 1000 regardless of data requested in the query,” maps the action “set maximum result size to 1000 records” for any query.
As previously described, in response to a query matching criteria included one of the rules 409, 411, 413, and 415, the system performs one or more actions mapped to the matched criterion. For example, a query can state, “SELECT NAME, EMP_NO FROM EMPLOYEES. Based on the content of the query (e.g., determined by query processor 133), the system can determine that only the criterion of rule 415 (“QUERY_PATTERN=ANY”) matches the query. Accordingly, as indicated by rule 415, the system can generate and execute database instructions (e.g., database instructions 163) restricting the retrieved records (e.g., database records 165) based on the action “set maximum result size to 1000 records”.
In another example a query can state, “SELET NAME, AVG(SALARY) FROM DEPT GROUP BY NAME.” Based on the content of the query, the system can determine that none of the rules 409, 411, 413, and 415 include criteria matching the query. Notably, the query includes the aggregation “AVG,” which is similar to the aggregations in rule 405 (e.g., SUM, MIN, MAX). However, as the query does not match criteria of any of the rules 409, 411, 413, and 415, the system can reject execution of the query.
In a further example, a query can state, “SELECT LEAVES.LEAVE ID, EMPLOYEES.EMP_NAME, LEAVES.LEAVEDATE FROM LEAVES INNER JOIN EMPLOYEES ON LEAVES.EMP_ID=EMPLOYEES.EMPLOYEE_ID.” Based on the content of the query, the system can determine that the query matches criteria of rules 411, 413, and 415. Accordingly, the system can perform the actions specified by each of the rules 411, 413, and 415, which include “Allow query execution, if not more than 1000 executions have happened in the last 5 minutes,” “Set they query time out to 30 seconds,” and “Limit the result set rows to 1000.”
According to one embodiment, the techniques described herein are implemented by one or more special-purpose computing devices. The special-purpose computing devices may be hard-wired to perform the techniques, or may include digital electronic devices such as one or more application-specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or network processing units (NPUs) that are persistently programmed to perform the techniques, or may include one or more general purpose hardware processors programmed to perform the techniques pursuant to program instructions in firmware, memory, other storage, or a combination. Such special-purpose computing devices may also combine custom hard-wired logic, ASICs, FPGAs, or NPUs with custom programming to accomplish the techniques. The special-purpose computing devices may be desktop computer systems, portable computer systems, handheld devices, networking devices or any other device that incorporates hard-wired and/or program logic to implement the techniques.
For example,
Computer system 500 also includes a main memory 506, such as a random access memory (RAM) or other dynamic storage device, coupled to bus 502 for storing information and instructions to be executed by processor 504. Main memory 506 also may be used for storing temporary variables or other intermediate information during execution of instructions to be executed by processor 504. Such instructions, when stored in non-transitory storage media accessible to processor 504, render computer system 500 into a special-purpose machine that is customized to perform the operations specified in the instructions.
Computer system 500 further includes a read only memory (ROM) 508 or other static storage device coupled to bus 502 for storing static information and instructions for processor 504. A storage device 510, such as a magnetic disk or optical disk, is provided and coupled to bus 502 for storing information and instructions.
Computer system 500 may be coupled via bus 502 to a display 512, such as a cathode ray tube (CRT), for displaying information to a computer user. An input device 514, including alphanumeric and other keys, is coupled to bus 502 for communicating information and command selections to processor 504. Another type of user input device is cursor control 516, such as a mouse, a trackball, or cursor direction keys for communicating direction information and command selections to processor 504 and for controlling cursor movement on display 512. This input device typically has two degrees of freedom in two axes, a first axis (e.g., x) and a second axis (e.g., y), that allows the device to specify positions in a plane.
Computer system 500 may implement the techniques described herein using customized hard-wired logic, one or more ASICs or FPGAs, firmware and/or program logic which in combination with the computer system causes or programs computer system 500 to be a special-purpose machine. According to one embodiment, the techniques herein are performed by computer system 500 in response to processor 504 executing one or more sequences of one or more instructions contained in main memory 506. Such instructions may be read into main memory 506 from another storage medium, such as storage device 510. Execution of the sequences of instructions contained in main memory 506 causes processor 504 to perform the process steps described herein. In alternative embodiments, hard-wired circuitry may be used in place of or in combination with software instructions.
The term “storage media” as used herein refers to any non-transitory media that store data and/or instructions that cause a machine to operate in a specific fashion. Such storage media may comprise non-volatile media and/or volatile media. Non-volatile media includes, for example, optical or magnetic disks, such as storage device 510. Volatile media includes dynamic memory, such as main memory 506. Common forms of storage media include, for example, a floppy disk, a flexible disk, hard disk, solid state drive, magnetic tape, or any other magnetic data storage medium, a CD-ROM, any other optical data storage medium, any physical medium with patterns of holes, a RAM, a PROM, and EPROM, a FLASH-EPROM, NVRAM, any other memory chip or cartridge, content-addressable memory (CAM), and ternary content-addressable memory (TCAM).
Storage media is distinct from but may be used in conjunction with transmission media. Transmission media participates in transferring information between storage media. For example, transmission media includes coaxial cables, copper wire and fiber optics, including the wires that comprise bus 502. Transmission media can also take the form of acoustic or light waves, such as those generated during radio-wave and infra-red data communications.
Various forms of media may be involved in carrying one or more sequences of one or more instructions to processor 504 for execution. For example, the instructions may initially be carried on a magnetic disk or solid state drive of a remote computer. The remote computer can load the instructions into its dynamic memory and send the instructions over a telephone line using a modem. A modem local to computer system 500 can receive the data on the telephone line and use an infra-red transmitter to convert the data to an infra-red signal. An infra-red detector can receive the data carried in the infra-red signal and appropriate circuitry can place the data on bus 502. Bus 502 carries the data to main memory 506, from which processor 504 retrieves and executes the instructions. The instructions received by main memory 506 may optionally be stored on storage device 510 either before or after execution by processor 504.
Computer system 500 also includes a communication interface 518 coupled to bus 502. Communication interface 518 provides a two-way data communication coupling to a network link 520 that is connected to a local network 522. For example, communication interface 518 may be an integrated services digital network (ISDN) card, cable modem, satellite modem, or a modem to provide a data communication connection to a corresponding type of telephone line. As another example, communication interface 518 may be a local area network (LAN) card to provide a data communication connection to a compatible LAN. Wireless links may also be implemented. In any such implementation, communication interface 518 sends and receives electrical, electromagnetic or optical signals that carry digital data streams representing various types of information.
Network link 520 typically provides data communication through one or more networks to other data devices. For example, network link 520 may provide a connection through local network 522 to a host computer 524 or to data equipment operated by an Internet Service Provider (ISP) 526. ISP 526 in turn provides data communication services through the world wide packet data communication network now commonly referred to as the “Internet” 528. Local network 522 and Internet 528 both use electrical, electromagnetic or optical signals that carry digital data streams. The signals through the various networks and the signals on network link 520 and through communication interface 518, which carry the digital data to and from computer system 500, are example forms of transmission media.
Computer system 500 can send messages and receive data, including program code, through the network(s), network link 520 and communication interface 518. In the Internet example, a server 530 might transmit a requested code for an application program through Internet 528, ISP 526, local network 522 and communication interface 518.
The received code may be executed by processor 504 as it is received, and/or stored in storage device 510, or other non-volatile storage for later execution.
Embodiments are directed to a system with one or more devices that include a hardware processor and that are configured to perform any of the operations described herein and/or recited in any of the claims below.
In an embodiment, a non-transitory computer readable storage medium comprises instructions which, when executed by one or more hardware processors, causes performance of any of the operations described herein and/or recited in any of the claims.
Any combination of the features and functionalities described herein may be used in accordance with one or more embodiments. In the foregoing specification, embodiments have been described with reference to numerous specific details that may vary from implementation to implementation. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense. The sole and exclusive indicator of the scope of the invention, and what is intended by the applicants to be the scope of the invention, is the literal and equivalent scope of the set of claims that issue from this application, in the specific form in which such claims issue, including any subsequent correction.
