# Error Prone

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)

This rule is defined by the following XPath expression:

    //FunctionCall[@Image='TO_DATE']
      [count(Arguments/ArgumentList/Argument) = 1]
      [Arguments/ArgumentList/Argument//FunctionCall[@Image='TO_CHAR']]

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)

This rule is defined by the following XPath expression:

    //FunctionCall[@Image='TO_DATE']
      [count(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)

This rule is defined by the following XPath expression:

    //FunctionCall[@Image='TO_TIMESTAMP']
      [count(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" />