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92-463: LINQ extends the language by the addition of query expressions , which are akin to SQL statements, and can be used to conveniently extract and process data from arrays , enumerable classes , XML documents, relational databases , and third-party data sources. Other uses, which utilize query expressions as a general framework for readably composing arbitrary computations, include the construction of event handlers or monadic parsers . It also defines

184-409: A .ndf extension, are used to allow the data of a single database to be spread across more than one file, and optionally across more than one file system. Log files are identified with the .ldf extension. Storage space allocated to a database is divided into sequentially numbered pages , each 8 KB in size. A page is the basic unit of I/O for SQL Server operations. A page is marked with

276-405: A .sql file, and are used either for management of databases or to create the database schema during the deployment of a database. SQLCMD was introduced with SQL Server 2005 and has continued through SQL Server versions 2008, 2008 R2, 2012, 2014, 2016 and 2019. Its predecessor for earlier versions was OSQL and ISQL, which were functionally equivalent as it pertains to T-SQL execution, and many of

368-501: A 16-bit server for the OS/2 operating system in 1989—and extends to the current day. Its name is entirely descriptive, it being server software that responds to queries in the SQL language. As of February 2024 , the following versions are supported by Microsoft: From SQL Server 2016 onward, the product is supported on x64 processors only and must have 1.4 GHz processor as

460-457: A 96-byte header which stores metadata about the page including the page number, page type, free space on the page and the ID of the object that owns it. The page type defines the data contained in the page. This data includes: data stored in the database, an index, an allocation map, which holds information about how pages are allocated to tables and indexes; and a change map which holds information about

552-564: A Microsoft-defined format, called Tabular Data Stream (TDS). TDS is an application layer protocol, used to transfer data between a database server and a client. Initially designed and developed by Sybase Inc. for their Sybase SQL Server relational database engine in 1984, and later by Microsoft in Microsoft SQL Server, TDS packets can be encased in other physical transport dependent protocols, including TCP/IP , named pipes , and shared memory . Consequently, access to SQL Server

644-444: A collection of XElement objects, which are then queried against using the local execution engine that is provided as a part of the implementation of the standard query operator. The LINQ to SQL provider allows LINQ to be used to query Microsoft SQL Server databases, including SQL Server Compact databases. Since SQL Server data may reside on a remote server, and because SQL Server has its own query engine, LINQ to SQL does not use

736-676: A component named SQL CLR ("Common Language Runtime") via which it integrates with .NET Framework . Unlike most other applications that use .NET Framework, SQL Server itself hosts the .NET Framework runtime , i.e., memory, threading and resource management requirements of .NET Framework are satisfied by SQLOS itself, rather than the underlying Windows operating system. SQLOS provides deadlock detection and resolution services for .NET code as well. With SQL CLR, stored procedures and triggers can be written in any managed .NET language , including C# and VB.NET . Managed code can also be used to define UDT's ( user defined types ), which can persist in

828-411: A database can also contain other objects including views , stored procedures , indexes and constraints , along with a transaction log. A SQL Server database can contain a maximum of 2 objects, and can span multiple OS-level files with a maximum file size of 2 bytes (1 exabyte). The data in the database are stored in primary data files with an extension .mdf . Secondary data files, identified with

920-718: A file in the filesystem. Notification Services was discontinued by Microsoft with the release of SQL Server 2008 in August 2008, and is no longer an officially supported component of the SQL Server database platform. SQL Server Integration Services (SSIS) provides ETL capabilities for SQL Server for data import , data integration and data warehousing needs. Integration Services includes GUI tools to build workflows such as extracting data from various sources, querying data, transforming data—including aggregation, de-duplication, de-/normalization and merging of data—and then exporting

1012-446: A first-class language construct and provide syntactic sugar for writing queries. These language extensions have initially been implemented in C# 3.0, VB 9.0 , F# and Oxygene , with other languages like Nemerle having announced preliminary support. The language extensions include: For example, in the query to select all the objects in a collection with SomeProperty less than 10,

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1104-419: A function, and hence an expression containing a function, may have side effects . An expression with side effects does not normally have the property of referential transparency . In many languages (e.g. C++ ), expressions may be ended with a semicolon ( ; ) to turn the expression into an expression statement . This asks the implementation to evaluate the expression for its side-effects only and to disregard

1196-472: A mapping designer that can be used to create the mapping between the data schemas in the object as well as the relational domain. It can automatically create the corresponding classes from a database schema , as well as allow manual editing to create a different view by using only a subset of the tables or columns in a table. The mapping is implemented by the DataContext that takes a connection string to

1288-491: A minimum, 2.0 GHz or faster is recommended. The current version is Microsoft SQL Server 2022, released November 16, 2022. The RTM version is 16.0.1000.6. Microsoft makes SQL Server available in multiple editions, with different feature sets and targeting different users. These editions are: Tools published by Microsoft include: The protocol layer implements the external interface to SQL Server. All operations that can be invoked on SQL Server are communicated to it via

1380-508: A new database, alter any existing database schema by adding or modifying tables and indexes, or analyze performance. It includes the query windows which provide a GUI based interface to write and execute queries. Azure Data Studio is a cross platform query editor available as an optional download. The tool allows users to write queries; export query results; commit SQL scripts to Git repositories and perform basic server diagnostics. Azure Data Studio supports Windows, Mac and Linux systems. It

1472-461: A part of the database engine, provides a reliable messaging and message queuing platform for SQL Server applications. Service broker services consists of the following parts: The message type defines the data format used for the message. This can be an XML object, plain text or binary data, as well as a null message body for notifications. The contract defines which messages are used in an conversation between services and who can put messages in

1564-400: A query, then the query optimizer looks at the database schema , the database statistics and the system load at that time. It then decides which sequence to access the tables referred in the query, which sequence to execute the operations and what access method to be used to access the tables. For example, if the table has an associated index, whether the index should be used or not: if the index

1656-483: A query. This can be SQL fragments or any other completely different representation of code as further manipulatable data. LINQ comes with LINQ Providers for in-memory object collections, Microsoft SQL Server databases, ADO.NET datasets and XML documents. These different providers define the different flavors of LINQ: The LINQ to Objects provider is used for in-memory collections, using the local query execution engine of LINQ. The code generated by this provider refers to

1748-435: A rank of their accurateness is computed. The results are returned to the client via the SQL Server process. SQLCMD is a command line application that comes with Microsoft SQL Server, and exposes the management features of SQL Server. It allows SQL queries to be written and executed from the command prompt. It can also act as a scripting language to create and run a set of SQL statements as a script. Such scripts are stored as

1840-472: A remote SQL server and push the script executions to it, or they can run a R or Python scripts as an external script inside a T-SQL query. The trained machine learning model can be stored inside a database and used for scoring. Used inside an instance, programming environment. For cross-instance applications, Service Broker communicates over TCP/IP and allows the different components to be synchronized, via exchange of messages. The Service Broker, which runs as

1932-442: A set of method names (called standard query operators , or standard sequence operators ), along with translation rules used by the compiler to translate query syntax expressions into expressions using fluent-style (called method syntax by Microsoft) with these method names, lambda expressions and anonymous types . In what follows, the descriptions of the operators are based on the application of working with collections. Many of

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2024-464: A single database session. SQL Server Native Client is used under the hood by SQL Server plug-ins for other data access technologies, including ADO or OLE DB . The SQL Server Native Client can also be directly used, bypassing the generic data access layers. On November 28, 2011, a preview release of the SQL Server ODBC driver for Linux was released. Microsoft SQL Server 2005 includes

2116-439: Is a GUI tool included with SQL Server 2005 and later for configuring, managing, and administering all components within Microsoft SQL Server. The tool includes both script editors and graphical tools that work with objects and features of the server. SQL Server Management Studio replaces Enterprise Manager as the primary management interface for Microsoft SQL Server since SQL Server 2005. A version of SQL Server Management Studio

2208-432: Is a syntactic entity in a programming language that may be evaluated to determine its value . It is a combination of one or more constants , variables , functions , and operators that the programming language interprets (according to its particular rules of precedence and of association ) and computes to produce ("to return", in a stateful environment) another value. This process, for mathematical expressions ,

2300-433: Is a mechanism for generating data-driven notifications, which are sent to Notification Services subscribers. A subscriber registers for a specific event or transaction (which is registered on the database server as a trigger); when the event occurs, Notification Services can use one of three methods to send a message to the subscriber informing about the occurrence of the event. These methods include SMTP, SOAP, or by writing to

2392-456: Is a report generation environment for data gathered from SQL Server databases. It is administered via a web interface. Reporting services features a web services interface to support the development of custom reporting applications. Reports are created as RDL files. Reports can be designed using recent versions of Microsoft Visual Studio (Visual Studio.NET 2003, 2005, and 2008) with Business Intelligence Development Studio , installed or with

2484-421: Is actually un-typed, which, in addition to lambda expressions being interpretable as either delegates or expression trees, allows for a great degree of flexibility for libraries wishing to expose parts of their interface as LINQ expression clauses. For example, LINQ to Objects works on IEnumerable<T> s and with delegates, whereas LINQ to SQL makes use of the expression trees. The expression trees are at

2576-526: Is also available for SQL Server Express Edition, for which it is known as SQL Server Management Studio Express (SSMSE). A central feature of SQL Server Management Studio is the Object Explorer, which allows the user to browse, select, and act upon any of the objects within the server. It can be used to visually observe and analyze query plans and optimize the database performance, among others. SQL Server Management Studio can also be used to create

2668-429: Is an expression because it denotes a value in memory , so y + 6 is also an expression. An example of a relational expression is 4 ≠ 4 , which evaluates to false . In C and most C-derived languages, a call to a function with a void return type is a valid expression, of type void. Values of type void cannot be used, so the value of such an expression is always thrown away. In many programming languages,

2760-933: Is available over these protocols. In addition, the SQL Server API is also exposed over web services . Data storage is a database , which is a collection of tables with typed columns. SQL Server supports different data types, including primitive types such as Integer , Float , Decimal , Char (including character strings), Varchar (variable length character strings), binary (for unstructured blobs of data), Text (for textual data) among others. The rounding of floats to integers uses either Symmetric Arithmetic Rounding or Symmetric Round Down ( fix ) depending on arguments: SELECT Round(2.5, 0) gives 3. Microsoft SQL Server also allows user-defined composite types (UDTs) to be defined and used. It also makes server statistics available as virtual tables and views (called Dynamic Management Views or DMVs). In addition to tables,

2852-415: Is called evaluation . In simple settings, the resulting value is usually one of various primitive types , such as string , boolean , or numerical (such as integer , floating-point , or complex ). Expressions are often contrasted with statements —syntactic entities that have no value (an instruction). 2 + 3 is both an arithmetic and programming expression, which evaluates to 5 . A variable

Language Integrated Query - Misplaced Pages Continue

2944-589: Is done in a background thread so that other operations do not have to wait for the I/O operation to complete. Each page is written along with its checksum when it is written. When reading the page back, its checksum is computed again and matched with the stored version to ensure the page has not been damaged or tampered with in the meantime. SQL Server allows multiple clients to use the same database concurrently. As such, it needs to control concurrent access to shared data, to ensure data integrity—when multiple clients update

3036-437: Is generated for a query, it is temporarily cached. For further invocations of the same query, the cached plan is used. Unused plans are discarded after some time. SQL Server also allows stored procedures to be defined. Stored procedures are parameterized T-SQL queries, that are stored in the server itself (and not issued by the client application as is the case with general queries). Stored procedures can accept values sent by

3128-400: Is limited to 8 KB in size. However, if the data exceeds 8 KB and the row contains varchar or varbinary data, the data in those columns are moved to a new page (or possibly a sequence of pages, called an allocation unit ) and replaced with a pointer to the data. For physical storage of a table, its rows are divided into a series of partitions (numbered 1 to n). The partition size

3220-591: Is managed by the Buffer Manager . Either reading from or writing to any page copies it to the buffer cache. Subsequent reads or writes are redirected to the in-memory copy, rather than the on-disc version. The page is updated on the disc by the Buffer Manager only if the in-memory cache has not been referenced for some time. While writing pages back to disc, asynchronous I/O is used whereby the I/O operation

3312-410: Is on a column which is not unique for most of the columns (low "selectivity"), it might not be worthwhile to use the index to access the data. Finally, it decides whether to execute the query concurrently or not. While a concurrent execution is more costly in terms of total processor time, because the execution is actually split to different processors might mean it will execute faster. Once a query plan

3404-489: Is the native client side data access library for Microsoft SQL Server, version 2005 onwards. It natively implements support for the SQL Server features including the Tabular Data Stream implementation, support for mirrored SQL Server databases, full support for all data types supported by SQL Server, asynchronous operations, query notifications, encryption support, as well as receiving multiple result sets in

3496-405: Is user defined; by default all rows are in a single partition. A table is split into multiple partitions in order to spread a database over a computer cluster . Rows in each partition are stored in either B-tree or heap structure. If the table has an associated, clustered index to allow fast retrieval of rows, the rows are stored in-order according to their index values, with a B-tree providing

3588-590: The ADO.NET APIs like any other managed application that accesses SQL Server data. However, doing that creates a new database session, different from the one in which the code is executing. To avoid this, SQL Server provides some enhancements to the ADO.NET provider that allows the connection to be redirected to the same session which already hosts the running code. Such connections are called context connections and are set by setting context connection parameter to true in

3680-512: The Wayback Machine ), JavaScript ( linq.js ), TypeScript ( linq.ts ), and ActionScript ( ActionLinq Archived 2018-12-25 at the Wayback Machine ), although none are strictly equivalent to LINQ in the .NET inspired languages C#, F# and VB.NET (where it is a part of the language, not an external library, and where it often addresses a wider range of needs). Expression (computer science) In computer science , an expression

3772-600: The XML for Analysis standard as the underlying communication protocol. The cube data can be accessed using MDX and LINQ queries. Data mining specific functionality is exposed via the DMX query language. Analysis Services includes various algorithms— Decision trees , clustering algorithm, Naive Bayes algorithm, time series analysis, sequence clustering algorithm, linear and logistic regression analysis, and neural networks —for use in data mining. SQL Server Reporting Services (SSRS)

Language Integrated Query - Misplaced Pages Continue

3864-547: The LINQ to DataSets. It uses ADO.NET to handle the communication with the database. Once the data is in ADO.NET Datasets, LINQ to DataSets execute queries against these datasets. Non-professional users may struggle with subtleties in the LINQ to Objects features and syntax. Naive LINQ implementation patterns can lead to a catastrophic degradation of performance. LINQ to XML and LINQ to SQL performance compared to ADO.NET depends on

3956-550: The SQL server instance, allowing people to do machine learning and data analytics without having to send data across the network or be limited by the memory of their own computers. The services come with Microsoft's R and Python distributions that contain commonly used packages for data science, along with some proprietary packages (e.g. revoscalepy , RevoScaleR , microsoftml) that can be used to create machine models at scale. Analysts can either configure their client machine to connect to

4048-536: The System.Linq namespace of the .NET framework. The PLINQ engine can execute parts of a query concurrently on multiple threads, providing faster results. Many of the concepts that LINQ introduced were originally tested in Microsoft's Cω research project, formerly known by the codenames X# (X Sharp) and Xen . It was renamed to Cω after Polyphonic C# (another research language based on join calculus principles)

4140-490: The aggregation to be arbitrary. Furthermore, a finalization function, taking the aggregation result to yet another value, can be supplied. This implement the Fold higher-order function. The standard query operator API also specifies certain operators that convert a collection into another type: While LINQ is primarily implemented as a library for .NET Framework 3.5, it also defines optional language extensions that make queries

4232-443: The changes made to other pages since last backup or logging, or contain large data types such as image or text. While a page is the basic unit of an I/O operation, space is actually managed in terms of an extent which consists of 8 pages. A database object can either span all 8 pages in an extent ("uniform extent") or share an extent with up to 7 more objects ("mixed extent"). A row in a database table cannot span more than one page, so

4324-427: The client application. For this it exposes read-only tables from which server statistics can be read. Management functionality is exposed via system-defined stored procedures which can be invoked from T-SQL queries to perform the management operation. It is also possible to create linked Servers using T-SQL. Linked servers allow a single query to process operations performed on multiple servers. SQL Server Native Client

4416-420: The client as input parameters, and send back results as output parameters. They can call defined functions, and other stored procedures, including the same stored procedure (up to a set number of times). They can be selectively provided access to . Unlike other queries, stored procedures have an associated name, which is used at runtime to resolve into the actual queries. Also because the code need not be sent from

4508-564: The client every time (as it can be accessed by name), it reduces network traffic and somewhat improves performance. Execution plans for stored procedures are also cached as necessary. T-SQL (Transact-SQL) is Microsoft's proprietary procedural language extension for SQL Server. It provides REPL (Read-Eval-Print-Loop) instructions that extend standard SQL's instruction set for Data Manipulation ( DML ) and Data Definition ( DDL ) instructions, including SQL Server-specific settings, security and database statistics management. It exposes keywords for

4600-510: The command line parameters are identical, although SQLCMD adds extra versatility. Microsoft Visual Studio includes native support for data programming with Microsoft SQL Server. It can be used to write and debug code to be executed by SQL CLR. It also includes a data designer that can be used to graphically create, view or edit database schemas. Queries can be created either visually or using code. SSMS 2008 onwards, provides intellisense for SQL queries as well. SQL Server Management Studio

4692-532: The connection string. SQL Server also provides several other enhancements to the ADO.NET API, including classes to work with tabular data or a single row of data as well as classes to work with internal metadata about the data stored in the database. It also provides access to the XML features in SQL Server, including XQuery support. These enhancements are also available in T-SQL Procedures in consequence of

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4784-479: The core of the LINQ extensibility mechanism, by which LINQ can be adapted for many data sources. The expression trees are handed over to LINQ Providers, which are data source-specific implementations that adapt the LINQ queries to be used with the data source. If they choose so, the LINQ Providers analyze the expression trees contained in a query in order to generate essential pieces needed for the execution of

4876-411: The database, identified by their respective transaction IDs. The main mode of retrieving data from a SQL Server database is querying for it. The query is expressed using a variant of SQL called T-SQL , a dialect Microsoft SQL Server shares with Sybase SQL Server due to its legacy. The query declaratively specifies what is to be retrieved. It is processed by the query processor, which figures out

4968-521: The database. Managed code is compiled to CLI assemblies and after being verified for type safety , registered at the database. After that, they can be invoked like any other procedure. However, only a subset of the Base Class Library is available, when running code under SQL CLR. Most APIs relating to user interface functionality are not available. When writing code for SQL CLR, data stored in SQL Server databases can be accessed using

5060-439: The data—no other user can access the data as long as the lock is held. Shared locks are used when some data is being read—multiple users can read from data locked with a shared lock, but not acquire an exclusive lock. The latter would have to wait for all shared locks to be released. Locks can be applied on different levels of granularity—on entire tables, pages, or even on a per-row basis on tables. For indexes, it can either be on

5152-464: The earlier Polyphonic C# project. First available in 2004 as a compiler preview, Cω's features were subsequently used by Microsoft in the creation of the LINQ features released in 2007 in .NET version 3.5 The concurrency constructs have also been released in a slightly modified form as a library, named Joins Concurrency Library , for C# and other .NET languages by Microsoft Research . Ports of LINQ exist for PHP ( PHPLinq Archived 2018-01-19 at

5244-530: The elapsed time evaluating an expression (even one with no other apparent side effects), is sometimes essential to the correct operation of a system, as behaviour in time is easily visible from outside the evaluation environment by other parts of the system with which it interacts, and might even be regarded as the primary effect such as when performing benchmark testing . It depends on the particular programming language specification whether an expression with no abstract side effects can legally be eliminated from

5336-761: The entire index or on index leaves. The level of granularity to be used is defined on a per-database basis by the database administrator. While a fine-grained locking system allows more users to use the table or index simultaneously, it requires more resources, so it does not automatically yield higher performance. SQL Server also includes two more lightweight mutual exclusion solutions—latches and spinlocks—which are less robust than locks but are less resource intensive. SQL Server uses them for DMVs and other resources that are usually not busy. SQL Server also monitors all worker threads that acquire locks to ensure that they do not end up in deadlocks —in case they do, SQL Server takes remedial measures, which in many cases are to kill one of

5428-433: The execution path by the processing environment in which the expression is evaluated. Microsoft SQL Server Microsoft SQL Server (Structured Query Language) is a proprietary relational database management system developed by Microsoft . As a database server , it is a software product with the primary function of storing and retrieving data as requested by other software applications —which may run either on

5520-471: The heap structure has performance advantages over the clustered structure. Both heaps and B-trees can span multiple allocation units. SQL Server buffers pages in RAM to minimize disk I/O. Any 8 KB page can be buffered in-memory, and the set of all pages currently buffered is called the buffer cache. The amount of memory available to SQL Server decides how many pages will be cached in memory. The buffer cache

5612-548: The implementation of the standard query operators as defined on the Sequence pattern and allows IEnumerable<T> collections to be queried locally. Current implementation of LINQ to Objects perform interface implementation checks to allow for fast membership tests, counts, and indexed lookup operations when they are supported by the runtime type of the IEnumerable. The LINQ to XML provider converts an XML document to

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5704-441: The included Report Builder . Once created, RDL files can be rendered in a variety of formats, including Excel, PDF , CSV , XML , BMP , EMF , GIF , JPEG , PNG , and TIFF , and HTML Web Archive. Originally introduced as a post-release add-on for SQL Server 2000, Notification Services was bundled as part of the Microsoft SQL Server platform for the first and only time with SQL Server 2005. SQL Server Notification Services

5796-482: The index. The data is in the leaf node of the leaves, and other nodes storing the index values for the leaf data reachable from the respective nodes. If the index is non-clustered, the rows are not sorted according to the index keys. An indexed view has the same storage structure as an indexed table. A table without a clustered index is stored in an unordered heap structure. However, the table may have non-clustered indices to allow fast retrieval of rows. In some situations

5888-474: The indexer (that creates the full text indexes) and the full text query processor. The indexer scans through text columns in the database. It can also index through binary columns, and use iFilters to extract meaningful text from the binary blob (for example, when a Microsoft Word document is stored as an unstructured binary file in a database). The iFilters are hosted by the Filter Daemon process. Once

5980-514: The indexer in case of updates. When a full text query is received by the SQL Server query processor, it is handed over to the FTS query processor in the Search process. The FTS query processor breaks up the query into the constituent words, filters out the noise words, and uses an inbuilt thesaurus to find out the linguistic variants for each word. The words are then queried against the inverted index and

6072-515: The introduction of the new XML Datatype (query, value, nodes functions). SQL Server also includes an assortment of add-on services. While these are not essential for the operation of the database system, they provide value added services on top of the core database management system. These services either run as a part of some SQL Server component or out-of-process as Windows Service and presents their own API to control and interact with them. The SQL Server Machine Learning services operates within

6164-401: The join, but result in different execution plans. In such case, SQL Server chooses the plan that is expected to yield the results in the shortest possible time. This is called query optimization and is performed by the query processor itself. SQL Server includes a cost-based query optimizer which tries to optimize on the cost, in terms of the resources it will take to execute the query. Given

6256-493: The network, or database caches on the client side. Replication Services follows a publisher/subscriber model, i.e., the changes are sent out by one database server ("publisher") and are received by others ("subscribers"). SQL Server supports three different types of replication: SQL Server Analysis Services (SSAS) adds OLAP and data mining capabilities for SQL Server databases. The OLAP engine supports MOLAP , ROLAP and HOLAP storage modes for data. Analysis Services supports

6348-430: The network. Also, service broker supports security features like network authentication (using NTLM , Kerberos , or authorization certificates ), integrity checking, and message encryption . SQL Server Replication Services are used by SQL Server to replicate and synchronize database objects, either in entirety or a subset of the objects present, across replication agents, which might be other database servers across

6440-410: The operations that can be performed on SQL Server, including creating and altering database schemas, entering and editing data in the database as well as monitoring and managing the server itself. Client applications that consume data or manage the server will leverage SQL Server functionality by sending T-SQL queries and statements which are then processed by the server and results (or errors) returned to

6532-558: The operators take other functions as arguments. These functions may be supplied in the form of a named method or anonymous function. The set of query operators defined by LINQ is exposed to the user as the Standard Query Operator (SQO) API . The query operators supported by the API are: These operators optionally take a function that retrieves a certain numeric value from each element in the collection and uses it to find

6624-400: The optimistic concurrency control mechanism, which is similar to the multiversion concurrency control used in other databases. The mechanism allows a new version of a row to be created whenever the row is updated, as opposed to overwriting the row, i.e., a row is additionally identified by the ID of the transaction that created the version of the row. Both the old as well as the new versions of

6716-467: The processing happens at the database server, local methods, which are not defined as a part of the lambda expressions representing the predicates, cannot be used. However, it can use the stored procedures on the server. Any changes to the result set are tracked and can be submitted back to the database server. Since the LINQ to SQL provider (above) works only with Microsoft SQL Server databases, in order to support any generic database, LINQ also includes

6808-416: The query engine of LINQ. Instead, it converts a LINQ query to a SQL query that is then sent to SQL Server for processing. However, since SQL Server stores the data as relational data and LINQ works with data encapsulated in objects, the two representations must be mapped to one another. For this reason, LINQ to SQL also defines a mapping framework. The mapping is done by defining classes that correspond to

6900-403: The queue. The queue acts as storage provider for the messages. They are internally implemented as tables by SQL Server, but do not support insert, update, or delete functionality. The service program receives and processes service broker messages. Usually the service program is implemented as stored procedure or CLR application. Routes are network addresses where the service broker is located on

6992-577: The result of the expression (e.g. x+1; ) unless it is a part of an expression statement that induces side-effects (e.g. y=x+1; or func1(func2()); ). The formal notion of a side effect is a change to the abstract state of the running program. Another class of side effects are changes to the concrete state of the computational system, such as loading data into cache memories . Languages that are often described as "side effect–free" will generally still have concrete side effects that can be exploited, for example, in side-channel attacks . Furthermore,

7084-415: The row are stored and maintained, though the old versions are moved out of the database into a system database identified as Tempdb . When a row is in the process of being updated, any other requests are not blocked (unlike locking) but are executed on the older version of the row. If the other request is an update statement, it will result in two different versions of the rows—both of them will be stored by

7176-485: The same computer or on another computer across a network (including the Internet). Microsoft markets at least a dozen different editions of Microsoft SQL Server, aimed at different audiences and for workloads ranging from small single-machine applications to large Internet-facing applications with many concurrent users . The history of Microsoft SQL Server begins with the first Microsoft SQL Server product—SQL Server 1.0,

7268-416: The same data, or clients attempt to read data that is in the process of being changed by another client. SQL Server provides two modes of concurrency control: pessimistic concurrency and optimistic concurrency . When pessimistic concurrency control is being used, SQL Server controls concurrent access by using locks. Locks can be either shared or exclusive. An exclusive lock grants the user exclusive access to

7360-445: The sequence of steps that will be necessary to retrieve the requested data. The sequence of actions necessary to execute a query is called a query plan . There might be multiple ways to process the same query. For example, for a query that contains a join statement and a select statement, executing join on both the tables and then executing select on the results would give the same result as selecting from each table and then executing

7452-526: The sequence they are specified in the query but are near each other, they are also considered a match. T-SQL exposes special operators that can be used to access the FTS capabilities. The Full Text Search engine is divided into two processes: the Filter Daemon process ( msftefd.exe ) and the Search process ( msftesql.exe ). These processes interact with the SQL Server. The Search process includes

7544-473: The server, and can be used to generate a Table<T> where T is the type to which the database table will be mapped. The Table<T> encapsulates the data in the table, and implements the IQueryable<;T> interface, so that the expression tree is created, which the LINQ to SQL provider handles. It converts the query into T-SQL and retrieves the result set from the database server. Since

7636-424: The source string, indicated by a Rank value which can range from 0 to 1000—a higher rank means a more accurate match. It also allows linguistic matching ("inflectional search"), i.e., linguistic variants of a word (such as a verb in a different tense) will also be a match for a given word (but with a lower rank than an exact match). Proximity searches are also supported, i.e., if the words searched for do not occur in

7728-410: The sum, minimum, maximum or average values of all the elements in the collection, respectively. Overloaded versions take no function and act as if the identity is given as the lambda. A generalized Sum / Min / Max. This operator takes a function that specifies how two values are combined to form an intermediate or the final result. Optionally, a starting value can be supplied, enabling the result type of

7820-463: The tables in the database, and containing all or a subset of the columns in the table as data members. The correspondence, along with other relational model attributes such as primary keys , are specified using LINQ to SQL-defined attributes . For example, This class definition maps to a table named Customers and the two data members correspond to two columns. The classes must be defined before LINQ to SQL can be used. Visual Studio 2008 includes

7912-459: The text is extracted, the Filter Daemon process breaks it up into a sequence of words and hands it over to the indexer. The indexer filters out noise words , i.e., words like A , And , etc., which occur frequently and are not useful for search. With the remaining words, an inverted index is created, associating each word with the columns they were found in. SQL Server itself includes a Gatherer component that monitors changes to tables and invokes

8004-494: The threads entangled in a deadlock and roll back the transaction it started. To implement locking, SQL Server contains the Lock Manager . The Lock Manager maintains an in-memory table that manages the database objects and locks, if any, on them along with other metadata about the lock. Access to any shared object is mediated by the lock manager, which either grants access to the resource or blocks it. SQL Server also provides

8096-560: The transformed data into destination databases or files. SQL Server Full Text Search service is a specialized indexing and querying service for unstructured text stored in SQL Server databases. The full text search index can be created on any column with character based text data. It allows for words to be searched for in the text columns. While it can be performed with the SQL LIKE operator, using SQL Server Full Text Search service can be more efficient. Full allows for inexact matching of

8188-447: The types of variables result , c and results all are inferred by the compiler in accordance to the signatures of the methods eventually used. The basis for choosing the methods is formed by the query expression-free translation result The C#3.0 specification defines a Query Expression Pattern along with translation rules from a LINQ expression to an expression in a subset of C# 3.0 without LINQ expressions. The translation thus defined

8280-715: The use case. Version 4 of the .NET framework includes PLINQ , or Parallel LINQ , a parallel execution engine for LINQ queries. It defines the ParallelQuery<;T> class. Any implementation of the IEnumerable<;T> interface can take advantage of the PLINQ engine by calling the AsParallel<;T>(this IEnumerable<T>) extension method defined by the ParallelEnumerable class in

8372-483: Was integrated into it. Cω attempts to make datastores (such as databases and XML documents) accessible with the same ease and type safety as traditional types like strings and arrays . Many of these ideas were inherited from an earlier incubation project within the WebData XML team called X# and Xen. Cω also includes new constructs to support concurrent programming ; these features were largely derived from

8464-615: Was released to General Availability in September 2018. Prior to release the preview version of the application was known as SQL Server Operations Studio. Business Intelligence Development Studio (BIDS) is the IDE from Microsoft used for developing data analysis and Business Intelligence solutions utilizing the Microsoft SQL Server Analysis Services , Reporting Services and Integration Services . It

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