Class: DBI::DBD::Pg::Database

Inherits:
BaseDatabase
  • Object
show all
Defined in:
lib/dbd/pg/database.rb

Overview

See DBI::BaseDatabase.

Constant Summary collapse

POSTGRESQL_to_XOPEN =

type map

{
      "boolean"                   => [DBI::SQL_CHAR, 1, nil],
      "character"                 => [DBI::SQL_CHAR, 1, nil],
      "char"                      => [DBI::SQL_CHAR, 1, nil],
      "real"                      => [DBI::SQL_REAL, 4, 6],
      "double precision"          => [DBI::SQL_DOUBLE, 8, 15],
      "smallint"                  => [DBI::SQL_SMALLINT, 2],
      "integer"                   => [DBI::SQL_INTEGER, 4],
      "bigint"                    => [DBI::SQL_BIGINT, 8],
      "numeric"                   => [DBI::SQL_NUMERIC, nil, nil],
      "time with time zone"       => [DBI::SQL_TIME, nil, nil],
      "timestamp with time zone"  => [DBI::SQL_TIMESTAMP, nil, nil],
      "bit varying"               => [DBI::SQL_BINARY, nil, nil], #huh??
      "character varying"         => [DBI::SQL_VARCHAR, nil, nil],
      "bit"                       => [DBI::SQL_TINYINT, nil, nil],
      "text"                      => [DBI::SQL_VARCHAR, nil, nil],
      nil                         => [DBI::SQL_OTHER, nil, nil]
}

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(dbname, user, auth, attr) ⇒ Database

See DBI::BaseDatabase#new. These attributes are also supported:

  • pg_async: boolean or strings 'true' or 'false'. Indicates if we're to use PostgreSQL's asyncrohonous support. 'NonBlocking' is a synonym for this.

  • AutoCommit: 'unchained' mode in PostgreSQL. Commits after each statement execution.

  • pg_client_encoding: set the encoding for the client.

  • pg_native_binding: Boolean. Indicates whether to use libpq native binding or DBI's inline binding. Defaults to true.


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# File 'lib/dbd/pg/database.rb', line 40

def initialize(dbname, user, auth, attr)
    hash = DBI::Utils.parse_params(dbname)

    if hash['dbname'].nil? and hash['database'].nil?
        raise DBI::InterfaceError, "must specify database"
    end

    hash['options'] ||= nil
    hash['tty'] ||= ''
    hash['host'] ||= 'localhost'
    hash['port'] = hash['port'].to_i unless hash['port'].nil? 

    @connection = PGconn.new(hash['host'], hash['port'], hash['options'], hash['tty'], 
                             hash['dbname'] || hash['database'], user, auth)

    @exec_method = :exec
    @in_transaction = false

    # set attribute defaults, and look for pg_* attrs in the DSN
    @attr = { 'AutoCommit' => true, 'pg_async' => false }
    hash.each do |key, value|
        @attr[key] = value if key =~ /^pg_./
    end
    @attr.merge!(attr || {})
    if @attr['pg_async'].is_a?(String)
        case @attr['pg_async'].downcase
        when 'true'
            @attr['pg_async'] = true
        when 'false'
            @attr['pg_async'] = false
        else
            raise InterfaceError, %q{'pg_async' must be 'true' or 'false'}
        end
    end

    @attr.each { |k,v| self[k] = v} 
    @attr["pg_native_binding"] = true unless @attr.has_key? "pg_native_binding"

    load_type_map

    self['AutoCommit'] = true    # Postgres starts in unchained mode (AutoCommit=on) by default 

rescue PG::Error => err
    raise DBI::OperationalError.new(err.message)
end

Instance Attribute Details

#type_mapObject (readonly)

Returns the value of attribute type_map


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# File 'lib/dbd/pg/database.rb', line 26

def type_map
  @type_map
end

Instance Method Details

#[](attr) ⇒ Object


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# File 'lib/dbd/pg/database.rb', line 232

def [](attr)
    case attr
    when 'pg_client_encoding'
        @connection.client_encoding
    when 'NonBlocking'
        @attr['pg_async']
    else
        @attr[attr]
    end
end

#[]=(attr, value) ⇒ Object


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# File 'lib/dbd/pg/database.rb', line 243

def []=(attr, value)
    case attr
    when 'AutoCommit'
        if @attr['AutoCommit'] != value then
            if value    # turn AutoCommit ON
                if @in_transaction
                    # TODO: commit outstanding transactions?
                    _exec("COMMIT")
                    @in_transaction = false
                end
            else        # turn AutoCommit OFF
                @in_transaction = false
            end
        end
    # value is assigned below
    when 'NonBlocking', 'pg_async'
        # booleanize input
        value = value ? true : false
        @pgexec = (value ? DBI::DBD::Pg::PgExecutorAsync : DBI::DBD::Pg::PgExecutor).new(@connection)
        # value is assigned to @attr below
    when 'pg_client_encoding'
        @connection.set_client_encoding(value)
    when 'pg_native_binding'
        @attr[attr] = value
    else
        if attr =~ /^pg_/ or attr != /_/
            raise DBI::NotSupportedError, "Option '#{attr}' not supported"
        else # option for some other driver - quitly ignore
            return
        end
    end
    @attr[attr] = value
end

#__blob_create(mode = PGconn::INV_READ) ⇒ Object

Create a BLOB.


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# File 'lib/dbd/pg/database.rb', line 434

def __blob_create(mode=PGconn::INV_READ)
    start_transaction unless @in_transaction
    @connection.lo_creat(mode)
rescue PG::Error => err
    raise DBI::DatabaseError.new(err.message) 
end

#__blob_export(oid, file) ⇒ Object

Export a BLOB to a file.


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# File 'lib/dbd/pg/database.rb', line 424

def __blob_export(oid, file)
    start_transaction unless @in_transaction
    @connection.lo_export(oid.to_i, file)
rescue PG::Error => err
    raise DBI::DatabaseError.new(err.message) 
end

#__blob_import(file) ⇒ Object

Import a BLOB from a file.


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# File 'lib/dbd/pg/database.rb', line 414

def __blob_import(file)
    start_transaction unless @in_transaction
    @connection.lo_import(file)
rescue PG::Error => err
    raise DBI::DatabaseError.new(err.message) 
end

#__blob_open(oid, mode = PGconn::INV_READ) ⇒ Object

Open a BLOB.


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# File 'lib/dbd/pg/database.rb', line 444

def __blob_open(oid, mode=PGconn::INV_READ)
    start_transaction unless @in_transaction
    @connection.lo_open(oid.to_i, mode)
rescue PG::Error => err
    raise DBI::DatabaseError.new(err.message) 
end

#__blob_read(oid, length) ⇒ Object

Read a BLOB and return the data.


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# File 'lib/dbd/pg/database.rb', line 464

def __blob_read(oid, length)
    blob = @connection.lo_open(oid.to_i, PGconn::INV_READ)

    if length.nil?
        data = @connection.lo_read(blob)
    else
        data = @connection.lo_read(blob, length)
    end

    # FIXME it doesn't like to close here either.
    # @connection.lo_close(blob)
    data
rescue PG::Error => err
    raise DBI::DatabaseError.new(err.message) 
end

Remove a BLOB.


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# File 'lib/dbd/pg/database.rb', line 454

def __blob_unlink(oid)
    start_transaction unless @in_transaction
    @connection.lo_unlink(oid.to_i)
rescue PG::Error => err
    raise DBI::DatabaseError.new(err.message) 
end

#__blob_write(oid, value) ⇒ Object

Write the value to the BLOB.


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# File 'lib/dbd/pg/database.rb', line 483

def __blob_write(oid, value)
    start_transaction unless @in_transaction
    blob = @connection.lo_open(oid.to_i, PGconn::INV_WRITE)
    res = @connection.lo_write(blob, value)
    # FIXME not sure why PG doesn't like to close here -- seems to be
    # working but we should make sure it's not eating file descriptors
    # up before release.
    # @connection.lo_close(blob)
    return res
rescue PG::Error => err
    raise DBI::DatabaseError.new(err.message)
end

#__set_notice_processor(proc) ⇒ Object

FIXME DOCUMENT


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# File 'lib/dbd/pg/database.rb', line 499

def __set_notice_processor(proc)
    @connection.set_notice_processor proc
rescue PG::Error => err
    raise DBI::DatabaseError.new(err.message) 
end

#__types(force = nil) ⇒ Object

return the postgresql types for this session. returns an oid -> type name mapping.


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# File 'lib/dbd/pg/database.rb', line 395

def __types(force=nil)
    load_type_map if (!@type_map or force)
    @type_map
end

#__types_oldObject

deprecated.


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# File 'lib/dbd/pg/database.rb', line 401

def __types_old
    h = { } 

    _exec('select oid, typname from pg_type').each do |row|
        h[row["oid"].to_i] = row["typname"]
    end

    return h
end

#_exec(sql, *parameters) ⇒ Object


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# File 'lib/dbd/pg/database.rb', line 310

def _exec(sql, *parameters)
    @pgexec.exec(sql, parameters)
end

#_exec_prepared(stmt_name, *parameters) ⇒ Object


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# File 'lib/dbd/pg/database.rb', line 314

def _exec_prepared(stmt_name, *parameters)
    @pgexec.exec_prepared(stmt_name, parameters)
end

#_prepare(stmt_name, sql) ⇒ Object


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# File 'lib/dbd/pg/database.rb', line 318

def _prepare(stmt_name, sql)
    @pgexec.prepare(stmt_name, sql)
end

#columns(table) ⇒ Object

See DBI::BaseDatabase.

These additional attributes are also supported:

  • nullable: true if NULL values are allowed in this column.

  • indexed: true if this column is a part of an index.

  • primary: true if this column is a part of a primary key.

  • unique: true if this column is a part of a unique key.

  • default: what will be insert if this column is left out of an insert query.

  • array_of_type: true if this is actually an array of this type. dbi_type will be the type authority if this is the case.


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# File 'lib/dbd/pg/database.rb', line 130

def columns(table)
    sql1 = %[
        select a.attname, i.indisprimary, i.indisunique
        from pg_class bc inner join pg_index i 
            on bc.oid = i.indrelid 
            inner join pg_class c 
                on c.oid = i.indexrelid 
                inner join pg_attribute a
                    on c.oid = a.attrelid
        where bc.relname = ?
            and bc.relkind in ('r', 'v')
            and pg_catalog.pg_table_is_visible(bc.oid);
    ]

    sql2 = %[
        SELECT a.attname, a.atttypid, a.attnotnull, a.attlen, format_type(a.atttypid, a.atttypmod) 
        FROM pg_catalog.pg_class c, pg_attribute a, pg_type t 
        WHERE a.attnum > 0 AND a.attrelid = c.oid AND a.atttypid = t.oid AND c.relname = ?
            AND c.relkind IN ('r','v')
        AND pg_catalog.pg_table_is_visible(c.oid)
    ]

    # by Michael Neumann (get default value)
    # corrected by Joseph McDonald
    sql3 = %[
        SELECT pg_attrdef.adsrc, pg_attribute.attname 
        FROM pg_attribute, pg_attrdef, pg_catalog.pg_class
        WHERE pg_catalog.pg_class.relname = ? AND 
        pg_attribute.attrelid = pg_catalog.pg_class.oid AND
                      pg_attrdef.adrelid = pg_catalog.pg_class.oid AND
                      pg_attrdef.adnum = pg_attribute.attnum
                      AND pg_catalog.pg_class.relkind IN ('r','v')
                      AND pg_catalog.pg_table_is_visible(pg_catalog.pg_class.oid)
    ]

    dbh = DBI::DatabaseHandle.new(self)
    dbh.driver_name = DBI::DBD::Pg.driver_name
    indices = {}
    default_values = {}

    dbh.select_all(sql3, table) do |default, name|
        default_values[name] = default
    end

    dbh.select_all(sql1, table) do |name, primary, unique|
        indices[name] = [primary, unique]
    end

    ########## 

    ret = []
    dbh.execute(sql2, table) do |sth|
        ret = sth.collect do |row|
            name, pg_type, notnullable, len, ftype = row
            #name = row[2]
            indexed = false
            primary = nil
            unique = nil
            if indices.has_key?(name)
                indexed = true
                primary, unique = indices[name]
            end

            typeinfo = DBI::DBD::Pg.parse_type(ftype)
            typeinfo[:size] ||= len

            if POSTGRESQL_to_XOPEN.has_key?(typeinfo[:type])
                sql_type = POSTGRESQL_to_XOPEN[typeinfo[:type]][0]
            else
                sql_type = POSTGRESQL_to_XOPEN[nil][0]
            end

            row = {}
            row['name']           = name
            row['sql_type']       = sql_type
            row['type_name']      = typeinfo[:type]
            row['nullable']       = ! notnullable
            row['indexed']        = indexed
            row['primary']        = primary
            row['unique']         = unique
            row['precision']      = typeinfo[:size]
            row['scale']          = typeinfo[:decimal]
            row['default']        = default_values[name]
            row['array_of_type']  = typeinfo[:array]

            if typeinfo[:array]
                row['dbi_type'] = 
                    DBI::DBD::Pg::Type::Array.new(
                        DBI::TypeUtil.type_name_to_module(typeinfo[:type])
                )
            end
            row
        end # collect
    end # execute

    return ret
end

#commitObject


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# File 'lib/dbd/pg/database.rb', line 277

def commit
    if @in_transaction
        _exec("COMMIT")
        @in_transaction = false
    else
        # TODO: Warn?
    end
end

#database_nameObject


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# File 'lib/dbd/pg/database.rb', line 106

def database_name
    @connection.db
end

#disconnectObject


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

def disconnect
    if not @attr['AutoCommit'] and @in_transaction
        _exec("ROLLBACK")   # rollback outstanding transactions
    end
    @connection.close
end

#in_transaction?Boolean

Are we in an transaction?

Returns:

  • (Boolean)

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# File 'lib/dbd/pg/database.rb', line 298

def in_transaction?
    @in_transaction
end

#pingObject


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# File 'lib/dbd/pg/database.rb', line 93

def ping
    answer = _exec("SELECT 1")
    if answer
        return answer.num_tuples == 1
    else
        return false
    end
rescue PG::Error
    return false
ensure
    answer.clear if answer
end

#prepare(statement) ⇒ Object


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# File 'lib/dbd/pg/database.rb', line 228

def prepare(statement)
    DBI::DBD::Pg::Statement.new(self, statement)
end

#rollbackObject


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# File 'lib/dbd/pg/database.rb', line 286

def rollback
    if @in_transaction
        _exec("ROLLBACK")
        @in_transaction = false
    else
        # TODO: Warn?
    end
end

#start_transactionObject

Forcibly initializes a new transaction.


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# File 'lib/dbd/pg/database.rb', line 305

def start_transaction
    _exec("BEGIN")
    @in_transaction = true
end

#tablesObject


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# File 'lib/dbd/pg/database.rb', line 110

def tables
    stmt = execute("SELECT c.relname FROM pg_catalog.pg_class c WHERE c.relkind IN ('r','v') and pg_catalog.pg_table_is_visible(c.oid)")
    res = stmt.fetch_all.collect {|row| row[0]} 
    stmt.finish
    res
end