Operation Must Use An Updateable Query Access Insert Syntax

Images/1482_4.jpg' alt='Operation Must Use An Updateable Query Access Insert Syntax' title='Operation Must Use An Updateable Query Access Insert Syntax' />This OGC Encoding Standard defines GeoPackages for exchange and GeoPackage SQLite Extensions for direct use of vector geospatial features and or tile matrix sets. Pes Patch 4.4 Crack on this page. SQL Server 2016 Service Pack 1 SP1 CREATE OR ALTER ltobject syntax is now available for procedures, views, functions, and triggers. Support for a more generic query. Understanding how SQL Server executes a query. If you are a developer writing applications that use SQL Server and you are wondering what exactly happens when you run a query from your application, I hope this article will help you write better database code and will help you get started when you have to investigate performance problems. SQL Server is a client server platform. The only way to interact with the back end database is by sending requests that contain commands for the database. The protocol used to communicate between your application and the database is called TDS Tabular Data Sream and is described on MSDN in the Technical Document MS TDS Tabular Data Stream Protocol. The application can use one of the several client side implementations of the protocol the CLR managed Sql. Client, Ole. DB, ODBC, JDBC, PHP Driver for SQL Server or the open source Free. TDS implementation. The gist of it is that when your application whats the database to do anything it will send a request over the TDS protocol. The request itself can take several forms Batch Request. This request type contains just T SQL text for a batch to be executed. This type of requests do not have parameters, but obviously the T SQL batch itself can contain local variables declarations. This is the type of request Sql. Client sends if you invoke any of the Sql. To retrieve data from the cache, add Cache to the table name. For example, to query cached data from the Sheet table, execute SELECT FROM SheetCache. Command. Execute. Reader, Execute. Non. Query, Execute. Scalar, Execute. Xml. Reader or they respective asyncronous equivalents on a Sql. Command object with an empty Parameters list. If you monitor with SQL Profiler you will see an SQL Batch. Starting Event Class. Remote Procedure Call Request. This request type contains a procedure identifier to execute, along with any number of parameters. Of special interest is when the procedure id will be 1. In this case the first parameter is the T SQL text to execute, and this is the request that what your application will send if you execute a Sql. Command object with a non empty Parameters list. If you monitor using SQL Profiler you will see an RPC Starting Event Class. Bulk Load Request. Bulk Load is a special type request used by bulk insert operations, like the bcp. IRowset. Fast. Load Ole. DB interface or by the Sql. Bulkcopy managed class. Bulk Load is different from the other requests because is the only request that starts execution before the request is complete on the TDS protocol. After a complete TDS request reaches the database engine SQL Server will create a task to handle the request. The list of requests in the server can be queried from sys. Tasks. The above mentioned task created to handle the request will represent the request from beginning till completion. For example if the request is a SQL Batch type request the task will represent the entire batch, not individual statements. Individual statements inside the SQL Batch will not create new tasks. Certain individual statements inside the batch may execute with parallelism often referred to as DOP, Degree Of Parallelism and in their case the task will spawn new sub tasks for executing in parallel. If the request returns a result the batch is complete when the result is completely consumed by the client eg. Sql. Data. Reader. You can see the list of tasks in the server by querying sys. When a new request reaches the server and the task is created to handle that request, in PENDING state. At this stage the server has no idea yet what the request actually is. The task has to start executing first, and for this the engine must assign a worker to it. Workers. Workers are the thread pool of SQL Server. A number of workers is created initially at server start up and more can be created on demand up to the configured max worker threads. Only workers execute code. Workers are waiting for PENDING tasks to become available from requests coming into the server and then each worker takes exactly one task and executes it. The worker is busy occupied until the task finishes completely. Tasks that are PENDING when there are no more available workers will have to wait until one of the executing running task completes and the worker that executed that task becomes available to execute another pending task. For a SQL batch request the worker that picks up that task will execute the entire SQL batch every statement. This should settle the often asked question whether statements in a SQL batch request task worker can execute in parallel no, as they are executed on a single thread worker then each statement must complete before the next one starts. For statements that internally use parallelism DOP 1 and create sub tasks, each sub task goes through exactly the same cycle it is created as PENDING and a worker must pick it up and execute it a different worker from the SQL batch worker, that is by definition occupied. The lists and state of workers inside SQL Server can be seen by querying sys. Parsing and Compilation. Once a task started executing a request the first thing it needs to do is to understand the content of the request. At this stage SQL Server will behave much like an interpreted language VM the T SQL text inside the request will be parsed and an abstract syntax tree will be created to represent the request. The entire request batch is parsed and compiled. If an error occurs at this stage, the requests terminates with a compilation error the request is then complete, the task is done and the worker is free to pick up another pending task. SQL, and T SQL, is a high end declarative language with extremely complex statements think SELECT with several JOINs. Compilation of T SQL batches does not result in executable code similar to native CPU instructions and not even similar to CLI instructions or JVM bytecode, but instead results primarily in data access plans or query plans. These plans describe the way to open the tables and indexes, search and locate the rows of interest, and do any data manipulation as requested in the SQL batch. For instance a query plan will describe an access path like open index idx. As a side note a common mistake done by developers is trying to come up with a single T SQL query that cover many alternatives, usually by using clever expressions in the WHERE clause, often having many OR alternatives eg. COLUMN parameter OR parameter IS NULL. For developers trying to keep things DRY and avoiding repetition are good practices, for SQL queries they are plain bad. The compilation has to come up with an access path that work for any value of the input parameters and the result is most often sub optimal. I cannot close this side without urging you to read Dynamic Search Conditions in T SQL if you want to learn more about this subject. Optimization. Speaking of choosing an optimal data access path, this is the next stage in the lifetime of the request optimization. In SQL, and in T SQL, optimization means choosing the best the data access path from all the possible alternatives. Consider that if you have a simple query with join between two tables and each table has an additional index there are already 4 possible ways to access the data and the number of possibilities grows exponentially as the query complexity increases and more alternative access paths are available basically, more indexes. Add to this that the JOIN can be done using various strategies nested loop, hash, merge and youll see why optimization is such an important concept in SQL.