Embedded SQL commands must appear in certain locations within
the FORTRAN program. Each embedded SQL command must be
accompanied by the prefix EXEC SQL. Comments may be placed
within an embedded command, and an embedded SQL command may
continue for several lines.
An embedded SQL command has no maximum length. A dynamic
SQL command can be no longer than 2048 bytes.
Location of SQL Commands |
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Put SQL commands, including their prefix, within columns 7
through 72 of either the main program unit or a subprogram unit:
INCLUDE SQLCA must appear in the Type Declaration Section of the
program unit which contains embedded SQL statements. The
INCLUDE command must appear before the BEGIN DECLARE SECTION
command.
BEGIN DECLARE SECTION and END DECLARE SECTION must appear as the
last declaration in the Type Declaration Section of the program
unit which contains embedded SQL statements. No variable type
declarations are allowed after the END DECLARE SECTION command.
All other SQL commands may appear after the END DECLARE SECTION
in either the main program unit or a subprogram unit.
Prefix |
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Precede each SQL command with the prefix EXEC SQL. Minimally
the prefix must be specified on the same line. For example,
the following are legal:
EXEC SQL SELECT PartName INTO :PartName
1 FROM PurchDB.Parts WHERE PartNumber = :PartNumber
EXEC SQL
1 SELECT PartName
2 INTO :PartName
3 FROM PurchDB.Parts
4 WHERE PartNumber = :PartNumber
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However, the following is not legal:
EXEC
1 SQL SELECT PartName INTO :PartName
2 FROM PurchDB.Parts WHERE PartNumber = :PartNumber
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FORTRAN Comments |
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You may insert FORTRAN comment lines within or between embedded
SQL commands. Denote comment lines by placing the letter C in
column 1 and entering the comment in columns 7 through 72:
EXEC SQL SELECT PartNumber, PartName
C put the data into the following host variables
1 INTO :PartNumber, :PartName
C find the data in the following table
2 FROM PurchDB.Parts
C retrieve only data that satisfies this search condition
3 WHERE PartNumber = :PartNumber
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SQL Comments |
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SQL comments can be inserted in any line of an SQL statement,
except the last line, by prefixing the comment character with at
least one space followed by two hyphens followed by one space:
EXEC SQL SELECT * FROM PurchDB.Parts -- This code selects Parts Table values.
WHERE SalesPrice > 500.;
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The comment terminates at the end of the current line.
(The decimal point in the 500 improves performance when being compared to
SalesPrice, which also has a decimal; no data type conversion is necessary.)
Continuation Lines |
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The FORTRAN preprocessor allows you to continue a non-numeric
literal from one line to the next. Enter any character other
than the digit 0 or a blank in column 6, and do not enter
the character C, *, or $ in column 1. The FORTRAN preprocessor
supports up to 19 continuation lines. The the FORTRAN/XL
compiler allows you to extend the number of continuation lines,
the FORTRAN compiler on other systems where the preprocessor is
used does not allow more than 19 contination lines. Therefore,
for consistency, the preprocessor only allows 19 contination
lines.
IF (PREDEFINEDCOMMENT .EQ. '5') THEN
EXEC SQL INSERT INTO PURCHDB.VENDORS
1 (VendorRemarks)
2 VALUES ('This vendor is bad news. Definitely place
3 no orders.')
ELSE
EXEC SQL INSERT INTO PURCHDB.VENDORS
1 (VendorRemarks)
2 VALUES (:VendorRemarks)
ENDIF
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