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To use cursors in SQL procedures, you need to do the following: Declare a cursor that defines a result set; Open the cursor to establish the result set; Fetch the data into local variables as needed from the cursor, one row at a time; Close the cursor when done; To work with cursors you must use the following SQL statements
Cursor-for loops automatically open a cursor, read in their data and close the cursor again. As an alternative, the PL/SQL programmer can pre-define the cursor's SELECT-statement in advance to (for example) allow re-use or make the code more understandable (especially useful in the case of long or complex queries).
SQL was initially developed at IBM by Donald D. Chamberlin and Raymond F. Boyce after learning about the relational model from Edgar F. Codd [12] in the early 1970s. [13] This version, initially called SEQUEL (Structured English Query Language), was designed to manipulate and retrieve data stored in IBM's original quasirelational database management system, System R, which a group at IBM San ...
Stored procedure. A stored procedure (also termed prc, proc, storp, sproc, StoPro, StoredProc, StoreProc, 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 ...
Query language. A query language, also known as data query language or database query language ( DQL ), is a computer language used to make queries in databases and information systems. In database systems, query languages rely on strict theory to retrieve information. [ 1] A well known example is the Structured Query Language (SQL).
Prepared statement. In database management systems (DBMS), a prepared statement, parameterized statement, or parameterized query is a feature where the database pre-compiles SQL code and stores the results, separating it from data. Benefits of prepared statements are: [1] efficiency, because they can be used repeatedly without re-compiling.
In SQL:1999 a recursive (CTE) query may appear anywhere a query is allowed. It's possible, for example, to name the result using CREATE [ RECURSIVE ] VIEW . [15] Using a CTE inside an INSERT INTO , one can populate a table with data generated from a recursive query; random data generation is possible using this technique without using any ...
SQL includes operators and functions for calculating values on stored values. SQL allows the use of expressions in the select list to project data, as in the following example, which returns a list of books that cost more than 100.00 with an additional sales_tax column containing a sales tax figure calculated at 6% of the price.