Rules to detect constructs that are either broken, extremely confusing or prone to runtime errors.
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TO_DATE_TO_CHAR

Since: PMD 5.1

Priority: Medium (3)

TO_DATE(TO_CHAR(date-variable)) used to remove time component - use TRUNC(date-variable)

//PrimaryExpression
    [PrimaryPrefix/Name/@Image='TO_DATE']
    [count(PrimarySuffix/Arguments/ArgumentList/Argument) = 1]
    [.//PrimaryExpression
        [PrimaryPrefix/Name/@Image='TO_CHAR']
        [count(PrimarySuffix/Arguments/ArgumentList/Argument) = 1]
    ]

Example(s):

CREATE OR REPLACE PACKAGE BODY date_utilities
IS

-- Take single parameter, relying on current default NLS date format
FUNCTION strip_time (p_date IN DATE) RETURN DATE
IS
BEGIN
   RETURN TO_DATE(TO_CHAR(p_date));
END strip_time;


END date_utilities;
/

Use this rule by referencing it:

<rule ref="category/plsql/errorprone.xml/TO_DATE_TO_CHAR" />

TO_DATEWithoutDateFormat

Since: PMD 5.1

Priority: Medium (3)

TO_DATE without date format- use TO_DATE(expression, date-format)

//PrimaryExpression[PrimaryPrefix/Name/@Image='TO_DATE'  and count(PrimarySuffix/Arguments/ArgumentList/Argument) = 1 ]

Example(s):

CREATE OR REPLACE PACKAGE BODY date_utilities
IS

-- Take single parameter, relying on current default NLS date format
FUNCTION to_date_single_parameter (p_date_string IN VARCHAR2) RETURN DATE
IS
BEGIN
   RETURN TO_DATE(p_date_string);
END to_date_single_parameter ;

-- Take 2 parameters, using an explicit date format string
FUNCTION to_date_two_parameters (p_date_string IN VARCHAR2, p_format_mask IN VARCHAR2) RETURN DATE
IS
BEGIN
   TO_DATE(p_date_string, p_date_format);
END to_date_two_parameters;

-- Take 3 parameters, using an explicit date format string and an explicit language
FUNCTION to_date_three_parameters (p_date_string IN VARCHAR2, p_format_mask IN VARCHAR2, p_nls_language VARCHAR2 ) RETURN DATE
IS
BEGIN
   TO_DATE(p_date_string, p_format_mask, p_nls_language);
END to_date_three_parameters;

END date_utilities;
/

Use this rule by referencing it:

<rule ref="category/plsql/errorprone.xml/TO_DATEWithoutDateFormat" />

TO_TIMESTAMPWithoutDateFormat

Since: PMD 5.1

Priority: Medium (3)

TO_TIMESTAMP without date format- use TO_TIMESTAMP(expression, date-format)

//PrimaryExpression[PrimaryPrefix/Name/@Image='TO_TIMESTAMP'  and count(PrimarySuffix/Arguments/ArgumentList/Argument) = 1 ]

Example(s):

CREATE OR REPLACE PACKAGE BODY date_utilities
IS

-- Take single parameter, relying on current default NLS date format
FUNCTION to_timestamp_single_parameter (p_date_string IN VARCHAR2) RETURN DATE
IS
BEGIN
   RETURN TO_TIMESTAMP(p_date_string);
END to_timestamp_single_parameter;

-- Take 2 parameters, using an explicit date format string
FUNCTION to_timestamp_two_parameters (p_date_string IN VARCHAR2, p_format_mask IN VARCHAR2) RETURN DATE
IS
BEGIN
   TO_TIMESTAMP(p_date_string, p_date_format);
END to_timestamp_two_parameters;

-- Take 3 parameters, using an explicit date format string and an explicit language
FUNCTION to_timestamp_three_parameters (p_date_string IN VARCHAR2, p_format_mask IN VARCHAR2, p_nls_language VARCHAR2 ) RETURN DATE
IS
BEGIN
   TO_TIMESTAMP(p_date_string, p_format_mask, p_nls_language);
END to_timestamp_three_parameters;

END date_utilities;
/

Use this rule by referencing it:

<rule ref="category/plsql/errorprone.xml/TO_TIMESTAMPWithoutDateFormat" />