Learn about Oracle PL/SQL stored procedures. Stored procedures in PL/SQL. A stored procedure can be shared by a number of programs. Stored procedures are helpful in controlling access to data.PL/SQL Procedures - Learn PL/SQL programming in simple and easy steps starting with PL/SQL. PL/SQL - Arrays; PL/SQL - Procedures; PL/SQL - Functions; PL/SQL. These subprograms are combined to form larger programs. Sample PL/SQL Programs. This appendix provides several PL/SQL programs to guide you in writing your own. Embedded PL/SQL Sample 6. DB2 allows stored procedures to be developed in a variety of ways. Stored Procedures can be based on a programming language such as C, C++, Java, or SQL PL. Stored Procedure creation and registration is very similar to User. This Oracle PL SQL tutorial teaches you the basics of programming in PL/SQL like cursors, stored procedures, PlSQL functions. How a Sample PL/SQL Block Looks. DECLARE Variable declaration BEGIN Program Execution EXCEPTION. Using Oracle PL/SQLResources. Note: The material on triggers that was formerly in this document has been. A New Document on Constraints and. Triggers. PL/SQL extends SQL by adding. SQL. The basic unit in PL/SQL is a block. Typically, each block performs a logical action in he program. A. block has the following structure. Declarative section: variables, types, and local subprograms. The other sections are optional. However, the SELECT statement has. Data definition statements like CREATE, DROP. ALTER are not allowed. The executable section also contains. C style comments (/* .. That type can be. One of the types used by SQL for database columns. A generic type used in PL/SQL such as NUMBER. Declared to be the same as the type of some database column. The most commonly used generic type is NUMBER. Variables of type. The most commonly used character. VARCHAR(n), where. This length is required, and there. For example, we might declare. NUMBER. my. Beer VARCHAR(2. Note that PL/SQL allows BOOLEAN variables, even though Oracle. BOOLEAN as a type for database columns. In many cases, a PL/SQL variable will. In this case. it is essential that the variable have the same type as the relation column. To be safe, instead of hard coding the type. TYPE operator. For example. Beer Beers. name%TYPE. PL/SQL variable my. Beer whatever type was declared for the. Beers. The result is a record type in which the fields have. For instance. beer. Tuple Beers%ROWTYPE. Tuple be a record with fields name. Beers(name. manufacture). The. assignment can occur either immediately after the type of the variable. An example. a NUMBER : = 3. The major nuance is that the form of the SELECT statement. SQL form. After the SELECT clause, we must. INTO clause listing variables, one for each attribute. SELECT clause, into which the components of the retrieved. The situation is essentially the same as that of the . If the query returns more than one tuple, you need to use a cursor. Here is an example. CREATE TABLE T1(. DELETE FROM T1. INSERT INTO T1 VALUES(1, 3). INSERT INTO T1 VALUES(2, 4). Above is plain SQL; below is the PL/SQL program. The INSERT statement thus inserts. T1. If you want a multiway branch, use. IF < condition. If not, we first. SELECT e,f INTO a,b FROM T1 WHERE e> 1. IF b=1 THEN. INSERT INTO T1 VALUES(b,a). INSERT INTO T1 VALUES(b+1. For example, here is. T1. of the above two examples. NUMBER : = 1. INSERT INTO T1 VALUES(i,i). EXIT WHEN i> 1. Use it inside a. conditional if you like. Also, < start> and < finish>. Cursors. A cursor is a variable that runs through the tuples of some relation. If the relation. is stored, we can also update or delete the tuple at the current cursor. It uses our example relation. The program will delete every tuple. T1. It ranges over. SELECT- FROM- WHERE. That query selects those tuples of T1 whose first component. Line (8) declares the cursor FOR. UPDATE since we will modify T1 using this cursor later on. Line (1. 4). In general, FOR UPDATE is unnecessary if the cursor. Notice that such a loop is bracketed. LOOP and END LOOP. Within the loop we find. On Line (1. 2), a fetch through the cursor into the local variables. In general. the FETCH statement must provide variables for each component. Since the query of Lines (5) through (7) produces. Its meaning should. NOTFOUND after the name of a cursor is true exactly. Here is an example of a PL/SQL procedure addtuple. CREATE TABLE T2 (. CREATE PROCEDURE addtuple. IN NUMBER) AS. INSERT INTO T2 VALUES(i, 'xxx'). An option is to follow CREATE. OR REPLACE. The advantage of doing so is that should you have. On the other hand. The possible modes are IN (read- only), OUT. INOUT (read and write). Note: Unlike. the type specifier in a PL/SQL variable declaration, the type specifier. For example, CHAR(1. VARCHAR(2. 0) are illegal; CHAR or VARCHAR. The actual length of a parameter depends on the. Then comes the body, which is essentially a PL/SQL block. We. have repeated the name of the procedure after the END, but this. However, the DECLARE section should not start. DECLARE. Rather, following AS we have. To execute the procedure. PL/SQL statement, in which the procedure is invoked as an executable. For example. BEGIN addtuple. END. . Because of this. OUT or INOUT parameter should. A constant or a literal argument should not be passed in. OUT/INOUT parameter. In a function declaration. RETURN and the type of the return. CREATE FUNCTION < func. Instead, it gives. A more couth way is to define a bind variable, which. Bind. variables are the kind that must be prefixed with a colon in PL/SQL statements. Jennifer Widom's CS1. Spring, 1. 99. 8; additional material. Jeff Ullman, Autumn 1. Jun Yang, Spring 1. Jennifer Widom, Spring 2.
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