ang dating daan articles - Updating two tables in sql

When you retrieve a nested table from the database into a PL/SQL variable, the rows are given consecutive subscripts starting at 1.

When the remote database uses a collection method such as , it uses its own character order, which might be different from the order where the collection originated.

If character set differences mean that two keys that were unique are not unique on the remote database, the program raises a Conceptually, a nested table is like a one-dimensional array with an arbitrary number of elements.

FIRST; 24 25 WHILE i IS NOT NULL LOOP 26 DBMS_Output.

PUT_LINE 27 ('Population of ' || i || ' is ' || TO_CHAR(city_population(i))); 28 i := city_population.

To create a collection or record variable, you first define a collection or record type, and then you declare a variable of that type. A collection that is created in a PL/SQL block (with the syntax in Collection) is available only in that block.

A nested table type or varray type that is created at schema level (with the CREATE TYPE Statement) is stored in the database, and you can manipulate it with SQL statements.Example 5-1 declares an associative array that is indexed by a string, populates it, and prints it.DECLARE 2 -- Associative array indexed by string: 3 4 TYPE population IS TABLE OF NUMBER -- Associative array type 5 INDEX BY VARCHAR2(64); 6 7 city_population population; -- Associative array variable 8 i VARCHAR2(64); 9 10 BEGIN 11 -- Add new elements to associative array: 12 13 city_population('Smallville') := 2000; 14 city_population('Midland') := 750000; 15 city_population('Megalopolis') := 1000000; 16 17 -- Change value associated with key 'Smallville': 18 19 city_population('Smallville') := 2001; 20 21 -- Print associative array: 22 23 i := city_population.NEXT(i); 29 END LOOP; 30 END; 31 / Population of Megalopolis is 1000000 Population of Midland is 750000 Population of Smallville is 2001 PL/SQL procedure successfully completed.SQL Like a database table, an associative array holds a data set of arbitrary size, and you can access its elements without knowing their positions in the array.These composite variables have internal components that you can treat as individual variables.

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