SQL Class 23 in Telugu/ DBMS / Normalization / 1NF /2 NF

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PLSQL CURSOR

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  CURSOR à In order to process SQL statements oracle will allocate an area of memory known as context area. PL/SQL uses it to store and execute SQL statements. The information retrieved from database which is available in context area is known as active set. A CURSOR is pointer which works on active set. CURSOR points one row at a time in context area. A CURSOR is used to process multiple rows using PL/SQL. à It is a private memory or buffer. It is used to hold the data from tables or views in memory location for manipulation purpose. It is valid in PL/SQL block only. à CURSORs are variables that you can define in the declaration section. à Types of CURSORs 1.Implicit Cursor 2.Explicit Cursor à 1.Implicit Cursor It is cursor that is automatically declared by oracle every time SQL statement is executed. They are identified by “SQL % <CURSOR ATTRIBUTES>”. When the executable part of the block is issued SQL statement, PL/SQL creates an implicit cursor. ...
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PL/SQL Class Notes 1-> Introduction , PLSQL Block structure,PLSQL Variables ,Banking Table creation,Nested Block, Labeled block

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  Pl/SQL Simple Notes Ø   PL/SQL is a procedural language and which is extension to a non-procedural language SQL. It is a block structured language. PL/SQL tells how to do, SQL tells what to do. Ø   A collection of Executable statements is called Block. Pl/SQL block is a logical collection of procedural and non-procedural statements. Ø   Pl/SQL features §   It is developed by oracle company in 1980’s. §   It is used by only oracle whereas SQL can be used by any RDBMS, DBMS technologies. §   It processes only one row at a time. §   It supports executable block of statements at once. §   It supports variables & Constraints, SQL-bind variables, PL/SQL bind and host variables. §   It supports error handling. §   It supports conditional statements (if, else, if-else). §   It supports interaction controls (while loop, for loop….). §   It supports sub-programs 1.     ...
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