---
name: "Bio::DB::Failover"
section: "3pm"
platform: "linux"
package: "libbio-perl-perl"
version: "1.7.8-1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/Bio::DB::Failover"
---

# Bio::DB::Failover(3pm)

A Bio::DB::RandomAccessI compliant class which wraps a prioritized list of DBs

## NAME

Bio::DB::Failover - A Bio::DB::RandomAccessI compliant class which wraps a prioritized list of DBs

## SYNOPSIS

```
    $failover = Bio::DB::Failover->new();
    $failover->add_database($db);
    # fail over Bio::DB::RandomAccessI.pm
    # this will check each database in priority, returning when
    # the first one succeeds
    $seq = $failover->get_Seq_by_id($id);
```

## DESCRIPTION

This module provides fail over access to a set of Bio::DB::RandomAccessI objects.

## CONTACT

Ewan Birney \<birney@ebi.ac.uk\> originally wrote this class.

### Support

Please direct usage questions or support issues to the mailing list:

*bioperl-l@bioperl.org*

rather than to the module maintainer directly. Many experienced and  reponsive experts will be able look at the problem and quickly  address it. Please include a thorough description of the problem  with code and data examples if at all possible.

### Reporting Bugs

Report bugs to the Bioperl bug tracking system to help us keep track the bugs and their resolution. Bug reports can be submitted via the web:

```
  https://github.com/bioperl/bioperl-live/issues
```

## APPENDIX

The rest of the documentation details each of the object methods. Internal methods are usually preceded with a \_

### add\_database

```
 Title   : add_database
 Usage   : add_database(%db)
 Function: Adds a database to the Failover object
 Returns : Count of number of databases
 Args    : Array of db resources
 Throws  : Not a RandomAccessI exception
```

### get\_Seq\_by\_id

```
 Title   : get_Seq_by_id
 Usage   : $seq = $db->get_Seq_by_id('ROA1_HUMAN')
 Function: Gets a Bio::Seq object by its name
 Returns : a Bio::Seq object
 Args    : the id (as a string) of a sequence
 Throws  : "no id" exception
```

### get\_Seq\_by\_acc

```
 Title   : get_Seq_by_acc
 Usage   : $seq = $db->get_Seq_by_acc('X77802');
 Function: Gets a Bio::Seq object by accession number
 Returns : A Bio::Seq object
 Args    : accession number (as a string)
 Throws  : "no id" exception
```

### get\_Seq\_by\_version

```
 Title   : get_Seq_by_version
 Usage   : $seq = $db->get_Seq_by_acc('X77802.2');
 Function: Gets a Bio::Seq object by versioned accession number
 Returns : A Bio::Seq object
 Args    : accession number (as a string)
 Throws  : "acc does not exist" exception
```