Class: DBI::DBD::Pg::Statement

Inherits:
BaseStatement
  • Object
show all
Defined in:
lib/dbd/pg/statement.rb

Overview

See DBI::BaseStatement, and DBI::DBD::Pg::Tuples.

– Peculiar Statement responsibilities:

- Translate dbi params (?, ?, ...) to Pg params ($1, $2, ...)
- Translate DBI::Binary objects to Pg large objects (lo_*)

Defined Under Namespace

Classes: DummyQuoter

Constant Summary collapse

PG_STMT_NAME_PREFIX = 
'ruby-dbi:Pg:'

Instance Method Summary collapse

Constructor Details

#initialize(db, sql) ⇒ Statement

Returns a new instance of Statement.



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# File 'lib/dbd/pg/statement.rb', line 13

def initialize(db, sql)
    super(db)
    @db  = db
    @sql = sql
    @stmt_name = PG_STMT_NAME_PREFIX + self.object_id.to_s + Time.now.to_f.to_s
    @result = nil
    @bindvars = []
    @prepared = false
rescue PGError => err
    raise DBI::ProgrammingError.new(err.message)
end

Instance Method Details

#[](attr) ⇒ Object

Attributes:

If pg_row_count is requested and the statement has already executed, postgres will return what it believes is the row count.



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# File 'lib/dbd/pg/statement.rb', line 100

def [](attr)
    case attr
    when 'pg_row_count'
        if @result
            @result.row_count
        else
            nil
        end
    else
        @attr[attr]
    end
end

#bind_param(index, value, options) ⇒ Object 



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# File 'lib/dbd/pg/statement.rb', line 25

def bind_param(index, value, options)
    @bindvars[index-1] = value
end

#column_info ⇒ Object

See DBI::DBD::Pg::Tuples#column_info.



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# File 'lib/dbd/pg/statement.rb', line 82

def column_info
    @result.column_info
end

#execute ⇒ Object

See DBI::BaseDatabase#execute.

This method will make use of PostgreSQL’s native BLOB support if DBI::Binary objects are passed in.



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# File 'lib/dbd/pg/statement.rb', line 35

def execute
    # replace DBI::Binary object by oid returned by lo_import
    @bindvars.collect! do |var|
        if var.is_a? DBI::Binary then
            oid = @db.__blob_create(PGconn::INV_WRITE)
            @db.__blob_write(oid, var.to_s)
            oid
        else
            var
        end
    end

    internal_prepare

    if not @db['AutoCommit'] then
        #          if not SQL.query?(boundsql) and not @db['AutoCommit'] then
        @db.start_transaction unless @db.in_transaction?
    end

    if @db["pg_native_binding"]
        pg_result = @db._exec_prepared(@stmt_name, *@bindvars)
    else
        pg_result = @db._exec_prepared(@stmt_name)
    end

    @result = DBI::DBD::Pg::Tuples.new(@db, pg_result)
rescue PGError, RuntimeError => err
    raise DBI::ProgrammingError.new(err.message)
end

#fetch ⇒ Object 



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# File 'lib/dbd/pg/statement.rb', line 65

def fetch
    @result.fetchrow
end

#fetch_scroll(direction, offset) ⇒ Object 



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# File 'lib/dbd/pg/statement.rb', line 69

def fetch_scroll(direction, offset)
    @result.fetch_scroll(direction, offset)
end

#finish ⇒ Object 



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# File 'lib/dbd/pg/statement.rb', line 73

def finish
    internal_finish
    @result = nil
    @db = nil
end

#rows ⇒ Object 



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# File 'lib/dbd/pg/statement.rb', line 86

def rows
    if @result
        @result.rows_affected
    else
        nil
    end
end