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<title>INGRES</title>
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<h1>INGRES</h1>
This driver implements read and write access for spatial data in
<a href="http://www.ingres.com/">INGRES</a> database tables. This
functionality was introduced in GDAL/OGR 1.6.0. <p>
When opening a database, it's name should be specified in the form
"@driver=ingres,dbname=<i>dbname</i>[,options]" where the options can
include comma seperated
items like "username=*userid*", "password=*password*", "timeout=*timeout*",
"tables=table1/table2". The driver and dbname values are required, while
the rest are optional. If username and password are not provided an attempt
is made to authenticate as the current user.<p>
Examples:
<pre>
@driver=ingres,dbname=test,userid=warmerda,password=test,tables=usa/canada
@driver=ingres,dbname=mapping
</pre>
If the tables list is not provided, an attempt is made to enumerate all
non-system tables as layers, otherwise only the listed tables are represented
as layers. This option is primarily useful when a database has a lot of
tables, and scanning all their schemas would take a significant amount of
time. <p>
If an integer field exists in a table that is named "ogr_fid" it will be
used as the FID, otherwise FIDs will be assigned sequentially. This can
result in different FIDs being assigned to a given record/feature depending
on the spatial and attribute query filters in effect at a given time.<p>
<p>By default, SQL statements are passed directly to the INGRES database
engine. It's also possible to request the driver to handle SQL commands
with <a href="/ogr/ogr_sql.html">OGR SQL</a> engine,
by passing <strong>"OGRSQL"</strong> string to the ExecuteSQL()
method, as name of the SQL dialect.</p>
Currently the INGRES driver supports only "old style" INGRES spatial data
types such as POLYGON, POINT, LINE, LONG POLYGON, LONG LINE, etc. It is
anticipated in the future a newer OGC compliant set of spatial types will
also be supported.<p>
<h2>Caveats</h2>
<ul>
<li> The spatial types CIRCLE and ICIRCLE are not currently supported for
reading. <p>
<li> No fast spatial index is used when reading, so spatial filters are
implemented by reading and parsing all records, and then discarding those
that do not satisfy the spatial filter.<p>
<li> There is currently no support for coordinate systems.<p>
</ul>
<h2>Creation Issues</h2>
The INGRES driver does not support creation of new datasets (a database
within INGRES), but it does allow creation of new layers (tables) within an
existing database instance.<P>
<ul>
<li>
The INGRES driver makes no allowances for character encodings at this time.<p>
<li>
The INGRES driver is not transactional at this time.<p>
<li> The spatial types BOX and IBOX are not supported for creating, and when
read are represented as polygons.<p>
<li> The non-LONG types (such as LINE, ILINE, and POLYGON) only support a
limited number of vertices. Attempts to create objects with more than the
maximum possible vertices for these types will fail. <p>
<li> The old ingres spatial types are very particular about geometry
validation, and attempts to insert (create) features with invalid geometries
will fail. Reasons for invalidity include self-intersection of linestrings,
and self-intersections for polygons. <p>
</ul>
<h3>Layer Creation Options</h3>
<ul>
<li>
<b>OVERWRITE</b>: This may be "YES" to force an existing layer of the
desired name to be destroyed before creating the requested layer.
</li>
<li>
<b>LAUNDER</b>: This may be "YES" to force new fields created on this
layer to have their field names "laundered" into a form more
compatible with MySQL. This converts to lower case and converts
some special characters like "-" and "#" to "_". If "NO" exact names
are preserved. The default value is "YES".
</li>
<li>
<b>PRECISION</b>: This may be "TRUE" to attempt to preserve field
widths and precisions for the creation and reading of MySQL layers.
The default value is "TRUE".
</li>
<li>
<b>GEOMETRY_NAME</b>: This option specifies the name of the
geometry column. The default value is "SHAPE".
</li>
<li>
<b>INGRES_FID</b>: This option specifies the name of the FID column.
The default value is "OGR_FID"
</li>
<li>
<b>GEOMETRY_TYPE</b>: Specifies the object type for the geometry
column. It may be one of POINT, LSEG, LINE, LONG LINE, POLYGON, or
LONG POLYGON. By default POINT, LONG LINE or LONG POLYGON are used
depending on the layer type.
</li>
</ul>
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