Embedded SQL commands must appear in certain locations
within the Pascal program.
Each embedded SQL command must be accompanied by a prefix and
followed by a semicolon.
Comments may be placed within
an embedded command, and non-numeric
literals in embedded commands may be
continued from one line to another.
An embedded SQL command has no maximum length. A dynamic SQL command can
be no longer than 2048 bytes as a literal string, but the maximum size of the host
variable is 32,762.
Location of SQL Commands |
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SQL commands must be put into the following specific areas:
BEGIN DECLARE SECTION and END DECLARE SECTION may appear
in any declaration section in a main program.
In a subprogram, these commands cannot appear in the global
declaration section.
All other SQL commands may appear in any statement part.
Prefix and Suffix |
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Precede each SQL command with the prefix EXEC SQL and
terminate each SQL command with a semicolon (;).
The entire prefix, EXEC SQL, must be specified on one line.
For example, the following examples are legal:
EXEC SQL SELECT PartName INTO :PartName
FROM Purchdb.Parts WHERE PartNumber = :PartNumber;
EXEC SQL SELECT PartName
INTO :PartName
FROM Purchdb.Parts
WHERE PartNumber = :PartNumber;
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However, the following is not legal:
EXEC
SQL SELECT PartName INTO :PartName
FROM Purchdb.Parts WHERE PartNumber = :PartNumber;
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Punctuation |
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SQL commands are always terminated with a semicolon (;).
Pascal Comments |
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You may insert Pascal comment lines within or between embedded SQL
commands. A comment begins with { and closes with
} or begins with (* and closes with *), as follows:
EXEC SQL SELECT PartNumber, PartName
{ put the data into the following host variables }
INTO :PartNumber, :PartName
(* find the data in the following table *)
FROM Purchdb.Parts
{ retrieve only data that satisfies this search condition *)
WHERE PartNumber = :PartNumber;
(* end of command }
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ALLBASE/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 > 500.0;
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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.)
