Stored procedure Wikipedia. A stored procedure also termed proc, storp, sproc, Sto. Pro, Stored. Proc, Store. Proc, sp, or SP is a subroutine available to applications that access a relational database management system RDBMS. Such procedures are stored in the database data dictionary. Uses for stored procedures include data validation integrated into the database or access control mechanisms. Furthermore, stored procedures can consolidate and centralize logic that was originally implemented in applications. To save time and memory, extensive or complex processing that requires execution of several SQL statements can be saved into stored procedures, and all applications call the procedures. One can use nested stored procedures by executing one stored procedure from within another. Stored procedures may return result sets, i. SELECT statement. Such result sets can be processed using cursors, by other stored procedures, by associating a result set locator, or by applications. Stored procedures may also contain declared variables for processing data and cursors that allow it to loop through multiple rows in a table. Stored procedure flow control statements typically include IF, WHILE, LOOP, REPEAT, and CASE statements, and more. Stored procedures can receive variables, return results or modify variables and return them, depending on how and where the variable is declared. ImplementationeditStored procedures are similar to user defined functions UDFs. The major difference is that UDFs can be used like any other expression within SQL statements, whereas stored procedures must be invoked using the CALL statement. CALL procedure. EXECUTE procedure. The exact and correct implementation of stored procedures varies from one database system to the other. SQLines provides tools and services to help you transfer data, convert database schema DDL, views, stored procedures, functions, triggers, queries and SQL scripts. A stored procedure also termed proc, storp, sproc, StoPro, StoredProc, StoreProc, sp, or SP is a subroutine available to applications that access a relational. Most major database vendors support them in some form. Depending on the database system, stored procedures can be implemented in a variety of programming languages, for example SQL, Java, C, or C. Stored procedures written in non SQL languages may or may not execute SQL statements themselves. The increasing adoption of stored procedures led to the introduction of procedural elements to the SQL language in the SQL 1. What is stored procedure in Sql server what are the advantages of using stored procedures in sql server. The SQL language is subdivided into several language elements, including Clauses, which are constituent components of statements and queries. In some cases, these. This is quite an obvious need in SSIS where you wanted to call Stored Procedure and keep its output in text file. This is one of the common and easy task to do in SQL. SQL 2. 00. 3 standards in the part SQLPSM. That made SQL an imperative programming language. Most database systems offer proprietary and vendor specific extensions, exceeding SQLPSM. A standard specification for Java stored procedures exists as well as SQLJRT. Comparison with dynamic SQLeditOverhead. Because stored procedure statements are stored directly in the database, they may remove all or part of the compiling overhead that is typically needed in situations where software applications send inline dynamic SQL queries to a database. However, most database systems implement statement caches and other methods to avoid repetitively compiling dynamic SQL statements. Also, while they avoid some pre compiled SQL, statements add to the complexity of creating an optimal execution plan because not all arguments of the SQL statement are supplied at compile time. Depending on the specific database implementation and configuration, mixed performance results will be seen from stored procedures versus generic queries or user defined functions. Avoiding network traffic. A major advantage of stored procedures is that they can run directly within the database engine. In a production system, this typically means that the procedures run entirely on a specialized database server, which has direct access to the data being accessed. The benefit here is that network communication costs can be avoided completely. I have a stored procedure that returns 80 columns, and 300 rows. I want to write a select that gets 2 of those columns. Something like SELECT col1, col2 FROM EXEC. This becomes more important for complex series of SQL statements. Encapsulating business logic. UPDATE-Stored-Procedure-in-SQL-Server-1.png' alt='Sql Server Stored Procedure Select Update Mysql' title='Sql Server Stored Procedure Select Update Mysql' />Stored procedures allow programmers to embed business logic as an API in the database, which can simplify data management and reduce the need to encode the logic elsewhere in client programs. This can result in a lesser likelihood of data corruption by faulty client programs. The database system can ensure data integrity and consistency with the help of stored procedures. Delegating access rights. In many systems, stored procedures can be granted access rights to the database that users who execute those procedures do not directly have. BfqC5.png' alt='Sql Server Stored Procedure Select Update Mysql' title='Sql Server Stored Procedure Select Update Mysql' />Some protection from SQL injection attacks. Stored procedures can be used to protect against injection attacks. Stored procedure parameters will be treated as data even if an attacker inserts SQL commands. Also, some DBMS will check the parameters type. However, a stored procedure that in turn generates dynamic SQL using the input is still vulnerable to SQL injections unless proper precautions are taken. Other useseditIn some systems, stored procedures can be used to control transaction management in others, stored procedures run inside a transaction such that transactions are effectively transparent to them. Stored procedures can also be invoked from a database trigger or a condition handler. For example, a stored procedure may be triggered by an insert on a specific table, or update of a specific field in a table, and the code inside the stored procedure would be executed. Writing stored procedures as condition handlers also allows database administrators to track errors in the system with greater detail by using stored procedures to catch the errors and record some audit information in the database or an external resource like a file. Comparison with functionseditA function is a subprogram written to perform certain computations. A scalar function returns only one value or NULL, whereas a table function returns a relational table comprising zero or more rows, each row with one or more columns. Functions must return a value using the RETURN keyword, but for stored procedures this is not mandatory. Stored procedures can use RETURN keyword but with no value being passed. Functions could be used in SELECT statements, provided they do no data manipulation. However, procedures cannot be included in SELECT statements. A stored procedure can return multiple values using the OUT parameter, or return no value. A stored procedure saves the query compiling time. A stored procedure is a database object. A stored procedure is a material object. Comparison with prepared statementseditPrepared statements take an ordinary statement or query and parameterize it so that different literal values can be used at a later time. Like stored procedures, they are stored on the server for efficiency and provide some protection from SQL injection attacks. Although simpler and more declarative, prepared statements are not ordinarily written to use procedural logic and cannot operate on variables. Because of their simple interface and client side implementations, prepared statements are more widely reusable between DBMS. DisadvantageseditStored procedure languages are often vendor specific. Changing database vendors usually requires rewriting existing stored procedures. Stored procedure languages from different vendors have different levels of sophistication. For example, Postgres pgpsql has more language features especially via extensions than Microsofts T SQL. Tool support for writing and debugging stored procedures is often not as good as for other programming languages, but this differs between vendors and languages. For example, both PLSQL and T SQL have dedicated IDEs and debuggers. PLPg. SQL can be debugged from various IDEs. Changes to stored procedures are harder to keep track of within a version control system than other code. Changes must be reproduced as scripts to be stored in the project history to be included, and differences in procedures can be harder to merge and track correctly. ReferenceseditExternal linksedit. Introduction to Change Data Capture CDC in SQL Server 2. Introduction. Often, youll be told that the specification of an application requires that  the value of  data in the database of an application must be recorded before it is changed. In other words, we are required to save all the history of the changes to the data. This feature is usually implemented for data security purposes. To implement this, I have seen a variety of solutions from triggers, timestamps and complicated queries stored procedures to audit data. SQL Server 2. 00. A better solution was introduced in SQL Server 2. Change Data Capture CDC. CDC has allowed SQL Server developers to deliver SQL Server data archiving and capturing without any additional programming. CDC is one of the new data tracking and capturing features of SQL Server 2. It only tracks changes in user created tables. Because captured data is then stored in relational tables, it can be easily accessed and retrieved subsequently, using regular T SQL. When you apply Change Data Capture features on a database table, a mirror of the tracked table is created with the same column structure of the original table, but with additional columns that include the metadata used to summarize the nature of the change in the database table row. The SQL Server DBA can then easily monitor the activity for the logged table using these new audit tables. Enabling Change Data Capture on a Database. CDC first has to be enabled for the database. Because CDC is a table level feature, it then has to be enabled for each table to be tracked. You can run following query and check whether it is enabled for any database. USE master. GOSELECT name, databaseid, iscdcenabled FROM sys. Update Center Norton Manual Auto Detect on this page. GO   This query will return the entire database name along with a column that shows whether  CDC is enabled. You can run this stored procedure in the context of each database to enable CDC at database level. The following script will enable CDC in Adventure. Works database. USE Adventure. Works. GOEXEC sys. GO As soon as CDC is enabled, it will show this result in SSMS. Additionally, in the database Adventure. Works, you will see that a schema with the name cdc has now been  created. Some System Tables will have been created within the  Adventure. Works database as part of the cdc schema. The table which have been created are listed here. This table returns result for list of captured column. This table returns list of all the tables which are enabled for capture. This table contains history of all the DDL changes since capture data enabled. This table contains indexes associated with change table. This table maps LSN number for which we will learn later and time. Enabling Change Data Capture on one or more Database Tables. The CDC feature can be applied at the table level  to any database for which CDC is enabled. It has to be enabled for any table which needs to be tracked. First run following query to show which tables of database have already been enabled for CDC. USE Adventure. Works. GOSELECT name, istrackedbycdc FROM sys. GO The above query will return a result that includes a column with the  table name, along with a column which displays if CDC is enabled or not. You can run the following stored procedure to enable each table. Before enabling CDC at the table level, make sure that you have  enabled SQL Server Agent. When CDC is enabled on a table, it creates two CDC related jobs that are specific to the database,  and executed using SQL Server Agent. Without SQL Server Agent enabled, these jobs will not execute. Additionally, it is very important to understand the role of the required parameter rolename. If there is any restriction of how data should be extracted from database, this option is used to specify any role which is following restrictions and gating access to data to this option if there is one. If you do not specify any role and, instead, pass a NULL value, data access to this changed table will not be tracked and will be available to access by everybody. Following script will enable CDC on Human. Resources. Shift table. USE Adventure. Works. GOEXEC sys. spcdcenabletablesourceschema  NHuman. Resources,sourcename    NShift,rolename      NULLGOAs we are using Adventure. Works database, it creates the jobs with following names. Adventure. Workscapture When this job is executed it runs the system stored procedure sys. MScdccapturejob. The procedure sys. MScdccapturejob. This procedure cannot be executed explicitly when a change data capture log scan operation is already active or when the database is enabled for transactional replication. This system SP enables SQL Server Agent, which in facts enable Change Data Capture feature. Adventure. Workscleanup When this job is executed it runs the system stored procedure sys. MScdccleanupjob. This system SP cleans up database changes tables. The Stored Procedure sys. CDC. There are several options available with this SP but we will only mention the required options for this SP. CDC is very powerful and versatile tool. By understanding the Stored Procedure  sys. CDC feature. One more thing to notice is that when these jobs are created they are automatically enabled as well. By default, all the columns of the specified table  is taken into consideration of this operation. If you want to only few columns of this table to be tracked in that case you can specify the columns as one of the parameters of above mentioned SP. When everything is successfully completed,  check  the system tables again and you will find a new table  called cdc. Human. ResourcesShiftCT. This table will contain all the changes in the table Human. Resources. Shift. If you expand this table, you will find five additional columns as well. As you will see there are five additional columnsto the mirrored original tablestartlsnendlsnseqvaloperationupdatemask. There are two values which are very important to us is operation and updatemask. Column operation contains value which corresponds to DML Operations. Following is quick list of value and its corresponding meaning. Delete Statement 1. Insert Statement 2. Value before Update Statement 3. Value after Update Statement 4. The column updatemask shows, via a bitmap,   which columns were updated in the DML operation that was specified by operation. If this was  a DELETE or INSERT operation,   all columns are updated and so the mask contains value which has all 1s in it. This mask is contains value which is formed with Bit values. Example of Change Data Capture. We will test this feature by doing  DML operations such as INSERT, UPDATE and DELETE on the table Human. Resources. Shift which we have set up for CDC. We will observe the effects on the CDC table cdc. Human. ResourcesShiftCT. Before we start lets first SELECT from both tables and see what is in them. USE Adventure. Works. GOSELECT FROM Human. Resources. Shift. GOUSE Adventure. Works. GOSELECT ROM cdc. Human. ResourcesShiftCTGOThe result  of the query is as displayed here. The original table Human. Resources. Shift has three rows in it, whereas the  table cdc. Human. ResourcesShiftCT is totally empty. This table will have entries after an operation on the tracked table. Insert Operation. Lets run an INSERT operation on the table Human. Resources. Shift. USE Adventure. Works. GOINSERT INTO Human. Resources. Shift       Name,Start. Time,End. Time,Modified. DateVALUES Tracked Shift,GETDATE, GETDATE, GETDATEGOOnce the script is run, we will check the content of two of our tables Human. Resources. Shift and cdc. Human. ResourcesShiftCT. Because of the INSERT operation, we have a newly inserted fourth row in the tracked table Human. Resources. Shift. The tracking table also has the same row visible. The value of operation is 2 which means that this is an INSERT operation. Update Operation. To illustrate the effects of an UPDATE we will update a newly inserted row. USEAdventure. Works.