# ESRI Personal GeoDatabase

OGR optionally supports reading ESRI Personal GeoDatabase .mdb files via ODBC. Personal GeoDatabase is a Microsoft Access database with a set of tables defined by ESRI for holding geodatabase metadata, and with geometry for features held in a BLOB column in a custom format (essentially Shapefile geometry fragments). This drivers accesses the personal geodatabase via ODBC but does not depend on any ESRI middle-ware.

Personal Geodatabases are accessed by passing the file name of the .mdb file to be accessed as the data source name. On Windows, no ODBC DSN is required. On Linux, there are problems with DSN-less connection due to incomplete or buggy implementation of this feature in the MDB Tools package, So, it is required to configure Data Source Name (DSN) if the MDB Tools driver is used (check instructions below).

In order to facilitate compatibility with different configurations, the PGEO_DRIVER_TEMPLATE Config Option was added to provide a way to programmatically set the DSN programmatically with the filename as an argument. In cases where the driver name is known, this allows for the construction of the DNS based on that information in a manner similar to the default (used for Windows access to the Microsoft Access Driver).

OGR treats all feature tables as layers. Most geometry types should be supported, including 3D data. Measures information will be discarded. Coordinate system information should be properly associated with layers.

Currently the OGR Personal Geodatabase driver does not take advantage of spatial indexes for fast spatial queries, though that may be added in the future.

By default, SQL statements are passed directly to the MDB database engine. It's also possible to request the driver to handle SQL commands with OGR SQL engine, by passing "OGRSQL" string to the ExecuteSQL() method, as name of the SQL dialect.

## How to use PGeo driver with unixODBC and MDB Tools (on Unix and Linux)

This article gives step-by-step explanation of how to use OGR with unixODBC package and how to access Personal Geodatabase with PGeo driver. See also GDAL wiki for other details

### Prerequisites

1. Install unixODBC >= 2.2.11
2. Install MDB Tools >= 0.6. I also tested with 0.5.99 (0.6 pre-release).

(On Ubuntu 8.04 : sudo apt-get install unixodbc libmdbodbc)

### Configuration

There are two configuration files for unixODBC:

- odbcinst.ini - this file contains definition of ODBC drivers available to all users; this file can be found in /etc directory or location given as --sysconfdir if you did build unixODBC yourself.
- odbc.ini - this file contains definition of ODBC data sources (DSN entries) available to all users.
- ~/.odbc.ini - this is the private file where users can put their own ODBC data sources.

Format of configuration files is very simple:

    [section_name]
    entry1 = value
    entry2 = value

For more details, refer to unixODBC manual.

#### 1. ODBC driver configuration

First, you need to configure ODBC driver to access Microsoft Access databases with MDB Tools. Add following definition to your odbcinst.ini file.

    [Microsoft Access Driver (*.mdb)]
    Description = MDB Tools ODBC drivers
    Driver     = /usr/lib/libmdbodbc.so.0
    Setup      =
    FileUsage  = 1
    CPTimeout  =
    CPReuse    =

- [Microsoft Access Driver (*.mdb)] - remember to use "Microsoft Access Driver (*.mdb)" as the name of section because PGeo driver composes ODBC connection string for Personal Geodatabase using "DRIVER=Microsoft Access Driver (*.mdb);" string.
- Description - put short description of this driver definition.
- Driver - full path of ODBC driver for MDB Tools.

#### 2. ODBC data source configuration

In this section, I use 'sample.mdb' as a name of Personal Geodatabase, so replace this name with your own database.

Create .odbc.ini file in your HOME directory:

    $ touch ~/.odbc.ini

Put following ODBC data source definition to your .odbc.ini file:

    [sample_pgeo]
    Description = Sample PGeo Database
    Driver      = Microsoft Access Driver (*.mdb)
    Database    = /home/mloskot/data/sample.mdb
    Host        = localhost
    Port        = 1360
    User        = mloskot
    Password    =
    Trace       = Yes
    TraceFile   = /home/mloskot/odbc.log

Step by step explanation of DSN entry:

- [sample_pgeo] - this is name of ODBC data source (DSN). You will refer to your Personal Geodatabase using this name. You can use your own name here.
- Description - short description of the DSN entry.
- Driver - full name of driver defined in step 1. above.
- Database - full path to .mdb file with your Personal Geodatabase.
- Host, Port, User and Password entries are not used by MDB Tools driver.

### Testing PGeo driver with ogrinfo

Now, you can try to access PGeo data source with ogrinfo.

First, check if you have PGeo driver built in OGR:

    $ ogrinfo --formats
    Supported Formats:
      ESRI Shapefile
      ...
      PGeo
      ...

Now, you can access your Personal Geodatabase. As a data source use PGeo:<DSN> where <DSN> is a name of DSN entry you put to your .odbc.ini.

    ogrinfo PGeo:sample_pgeo
    INFO: Open of `PGeo:sample_pgeo'
    using driver `PGeo' successful.
    1. ...

After you run the command above, you should get list of layers stored in your geodatabase.

Now, you can try to query details of particular layer:

    ogrinfo PGeo:sample_pgeo <layer name>
    INFO: Open of `PGeo:sample_pgeo'
    using driver `PGeo' successful.

    Layer name: ...

## Resources

- About ESRI Geodatabase
- [mdbtools-dev] DSN-less connection not supported?

If you have any comments or questions, don't hesitate to post them on the gdal-dev@lists.maptools.org mailing list.