Embedded SQL (Cont.)Pertemuan 10

Matakuliah : T0413/Current Popular IT IITahun : 2007

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Learning Outcomes

Pada akhir pertemuan ini, diharapkan mahasiswa akan mampu menciptakan aplikasi sistem basisdata menggunakan konsep embeded SQL di dalam program

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Outline Materi

• Using host language variables with SQL• Using SQLCODE and SQLSTATE• Updating cursors• Indicator variables• Examples

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Using Host language variables with SQL

• We can use variables from the host program in embedded SQL state

• Host variable must :– Be declared in a SQL DECLARE SECTION– Compatible data type

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Using Host language variables with SQL (Cont.)

• Be assign a value at the time they are used in the SQL statement

• Be preceed by a colon (:)

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DECLARING VARIABLE

• BEGIN DECLARE SECTION• END BEGIN SECTION

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RETRIEVING VALUES INTO VARIABLE

• Use SELECT INTO• Constraint : can’t retrieves multiple

rows and inserted into the same variables at the same time

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USING CURSOR• Example :

EXEC SQL DECLARE cursor londonstate FOR

SELECT * FROM salesPeopleWHERE city = ‘London’

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USING CURSOR• FETCH• OPEN CURSOR• CLOSE CURSOR

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USING SQL CODE AND SQL STATE

• SQL CODE• SQL STATE

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UPDATING CURSOR• Use cursor to select a group of rows

from a table that can be Updated and Deleted

• Example : increasing the comission of all sales people who have customers with a rating of 300 in the following example

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EXAMPLE UPDATING CURSOR• EXEC SQL OPEN CURSOR High_Cust

while SQLSTATE=‘00000’ dobeginEXECT SQL FETCH High_CustINTO : id_num, :salesperson, :loc, :comm;end;EXECT SQL UPDATE salespeopleSET comm = comm + .01WHERE CURRENT OF High_cust;

end;EXECT SQL CLOSE CURSOR High_Cust;

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INDICATOR VARIABLES• SQLNULL• SQLSTATE• SQLCODE• SQL EXACT NUMERIC

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OTHER USES OF INDICATOR VARIABLES

• USED TO INDICATE TRUNCATION• TO ASSIGN NULL VALUES