Module: DBI::DBD::Pg

Defined in:
lib/dbd/Pg.rb,
lib/dbd/pg/exec.rb

Overview

DBD::Pg - Database Driver for the PostgreSQL database system.

Requires DBI and the ‘pg’ gem or package to work.

Only things that extend DBI’s results are documented.

Defined Under Namespace

Modules: Type Classes: Database, Driver, PgExecutor, PgExecutorAsync, Statement, Tuples

Constant Summary collapse

VERSION = 
DBI::VERSION
DESCRIPTION = 
"PostgreSQL DBI DBD"

Class Method Summary collapse

Class Method Details

.driver_name ⇒ Object

returns ‘Pg’

See DBI::TypeUtil#convert for more information.



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# File 'lib/dbd/Pg.rb', line 60

def self.driver_name
    "Pg"
end

.generate_array(obj) ⇒ Object

This method takes a ruby Array and converts it to PostgreSQL array syntax.



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# File 'lib/dbd/Pg.rb', line 67

def self.generate_array(obj)
    # XXX yarr, there be recursion here, and it's probably not a good idea.
    output = "{"
    obj.each do |item|
        case item
        when ::Array
            output += generate_array(item)
        else
            generated = DBI::TypeUtil.convert(driver_name, item)
            generated = case item
                        when String
                            # in strings, escapes are doubled and the quotes are different.
                            # this gets *really* ugly and needs to be well-tested
                            "\"#{generated.gsub(/\\/) { "\\\\" }}\""
            # Since Ruby 2.4 Fixnum was deprecated, see https://bugs.ruby-lang.org/issues/12005
                        when Integer
                            generated.to_s
                        end
            output += generated
        end
        output += "," # FIXME technically, delimiters are variable
    end

    output.sub(/,$/, '}')
end

.parse_type(ftype) ⇒ Object

Parse a postgresql type. Returns a hash with these fields (as Symbol)

  • ftype: the full type, as passed in to this method.

  • type: the type stripped of all attribute information.

  • size: the LHS of the attribute information, typically the precision.

  • decimal: the RHS of the attribute information, typically the scale.

  • array: true if this type is actually an array of that type.



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# File 'lib/dbd/Pg.rb', line 109

def self.parse_type(ftype)
    type = ftype
    pos = ftype.index('(')
    decimal = nil
    size = nil
    array_of_type = nil

    if pos != nil
        type = ftype[0..pos-1]
        size = ftype[pos+1..-2]
        pos = size.index(',')
        if pos != nil
            size, decimal = size.split(',', 2)
            size = size.to_i
            decimal = decimal.to_i
        else
            size = size.to_i
        end
    end

    if type =~ /\[\]$/
        type.sub!(/\[\]$/, '')
        array_of_type = true
    end

    return {
        :ftype   => ftype.dup,
        :type    => type,
        :size    => size,
        :decimal => decimal,
        :array   => array_of_type
    }
end

.quote(value) ⇒ Object

A quote helper, this uses the new syntax in PostgreSQL 8.2 and up.



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# File 'lib/dbd/Pg.rb', line 96

def self.quote(value)
    "E'#{ value.gsub(/\\/){ '\\\\' }.gsub(/'/){ '\\\'' } }'"
end