Module: DWH::Functions

Includes:
Arrays, Dates, ExtractDatePart, Nulls
Included in:
Adapters::Adapter
Defined in:
lib/dwh/functions.rb,
lib/dwh/functions/dates.rb,
lib/dwh/functions/nulls.rb,
lib/dwh/functions/arrays.rb,
lib/dwh/functions/extract_date_part.rb

Overview

The Functions module adds a translation layer between this library and native database functions. It relies on the adapters settings file to map standard function to its native counterpart.

Examples:

Truncate date to the week start day

truncate_date('week', 'my_date_col')
Postgres ==> DATE_TRUNC('week', 'my_date_col')
SQL Server ==> DATETRUNC(week, 'my_date_col')

Output a date string as a valid date literal

date_literal('2025-08-06')
Postgres ==> '2025-08-06'::DATE
SQL Server ==> '2025-08-06'

Defined Under Namespace

Modules: Arrays, Dates, ExtractDatePart, Nulls

Constant Summary

Constants included from Dates

Dates::DATE_CLASSES, Dates::TIMESTAMPABLE_UNITS

Instance Method Summary collapse

Methods included from Arrays

#array_exclude_list, #array_in_list, #array_unnest_join

Methods included from Nulls

#if_null, #null_if, #null_if_zero

Methods included from ExtractDatePart

#extract_day_name, #extract_day_of_month, #extract_day_of_week, #extract_day_of_year, #extract_hour, #extract_minute, #extract_month, #extract_month_name, #extract_quarter, #extract_week_of_year, #extract_year, #extract_year_month

Methods included from Dates

#adjust_week_start_day, #adjust_week_start_day?, #current_date, #current_time, #current_timestamp, #date_add, #date_data_type, #date_diff, #date_format, #date_format_sql, #date_int?, #date_lit, #date_literal, #date_time_format, #date_time_literal, #date_time_tz_format, #default_week_start_day, #timestamp_lit, #timestamp_literal, #truncate_date, #week_start_day, #week_starts_on_sunday?

Instance Method Details

#cast(exp, type) ⇒ Object

Casts an expresion/literal to the target datatype. Datatype should be valid for the target db.

Parameters:

  • exp (String) —

    sql expression

  • type (String) —

    valid type for target db



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# File 'lib/dwh/functions.rb', line 31

def cast(exp, type)
  gsk(:cast).gsub(/@exp/i, exp)
            .gsub(/@type/i, type)
end

#cross_join(relation) ⇒ Object

Applies adapter specific cross join expression This takes the target table. Ie if you are joining table a with table b.. You will pass in the table b name expression here.

Examples:

adapter.cross_join("schema.table_b")

Parameters:

  • relation (String) —
    • table name or table exp


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# File 'lib/dwh/functions.rb', line 74

def cross_join(relation)
  gsk(:cross_join).sub(/@relation/i, relation)
end

#gsk(key) ⇒ String

Shortcut to get settings value by key.

Parameters:

  • key (Symbol, String)

Returns:

  • (String) —

    upcased value



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# File 'lib/dwh/functions.rb', line 82

def gsk(key)
  settings[key.to_sym]
end

#lower_case(exp) ⇒ Object 



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# File 'lib/dwh/functions.rb', line 40

def lower_case(exp)
  gsk(:lower_case).gsub(/@exp/i, exp)
end

#quote(exp) ⇒ Object

Applies adapter specific quotes around the given expression. The expression is usually a column name, alias, or table alias.

Parameters:

  • exp (String) —
    • column, alias, table name


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# File 'lib/dwh/functions.rb', line 53

def quote(exp)
  gsk(:quote).sub(/@exp/i, exp)
end

#string_lit(exp) ⇒ Object

Applies adapter specific string literal translation around the given expression. The expression is usually a string value.

Parameters:

  • exp (String) —

    some string value



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# File 'lib/dwh/functions.rb', line 61

def string_lit(exp)
  gsk(:string_literal).sub(/@exp/i, exp.gsub("'", "''"))
end

#trim(exp) ⇒ Object 



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# File 'lib/dwh/functions.rb', line 36

def trim(exp)
  gsk(:trim).gsub(/@exp/i, exp)
end

#upper_case(exp) ⇒ Object 



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# File 'lib/dwh/functions.rb', line 44

def upper_case(exp)
  gsk(:upper_case).gsub(/@exp/i, exp)
end