Introduction to
ArcSDE
Environmental, Earth & Ocean
Science 381
- Spring 2011 -
EEOS 381 Spring 2011 – Lecture 6
What is ArcSDE?
• Software product from ESRI
– “Spatial Database Engine”
– Part of ArcGIS system
– Stores and manages spatial data in a commercial
RDBMS
• Interface or gateway (“middleware”) between
ArcGIS applications and an RDBMS
– Oracle, Microsoft SQL Server and SQL Server Express,
IBM DB2, IBM Informix
– PostgreSQL (Open Source RDBMS, supported at 9.3+)
EEOS 381 Spring 2011 – Lecture 6
What is ArcSDE?
• Typically installed on a server (for the Enterprise version)
– Windows
– Unix, Linux
• Desktop and Workgroup SDE can be installed on your
own PC as well
ArcSDE GDBs
have all
functionality of
file and personal
GDBs
EEOS 381 Spring 2011 – Lecture 6
What is ArcSDE?
• ESRI definition:
– ArcSDE technology is a core component of ArcGIS
Server. It manages spatial data in a relational
database management system (RDBMS) and enables
it to be accessed by ArcGIS clients.
– It is the technology that provides the framework to
support long transactions, which facilitates the
versioned editing environment in multiuser
geodatabases. The geodatabase is the primary data
storage model for ArcGIS; it provides
a single central location to access
and manage spatial data.
EEOS 381 Spring 2011 – Lecture 6
What is ArcSDE?
• A geographic data server
– “Enterprise geodatabase”
• many users, large volume of data, accessed across
an entire organization or over Internet (“scalable”)
– RDBMS physically stores relational tables
• vector, raster, tabular data (expanding functionality
of RDBMS), metadata, …
– ArcSDE “interprets” the contents for use in
GIS software
• ArcGIS, ArcIMS, ArcView 3.x (via Database Access
extension) and ArcInfo Workstation
EEOS 381 Spring 2011 – Lecture 6
ArcSDE as Part of ArcGIS
The 3-tier
architecture
EEOS 381 Spring 2011 – Lecture 6
ArcSDE as Part of ArcGIS
The 3-tier
architecture
From 9.2 forward,
ArcSDE is
bundled with
ArcGIS Server.
ArcSDE is no
longer sold as a
separate product.
EEOS 381 Spring 2011 – Lecture 6
Benefits of ArcSDE
• Centralized spatial database
– Large volume of data
– Seamless, non-tiled layers
– Rapid spatial searching
– Storage and integration of vector, raster, tabular data
– Database and application portability
• Concurrent access for MANY users
– Versioning/Multi-user editing
– Clients connect over TCP/IP network (e.g. WEB)
– “Direct connect” also available
EEOS 381 Spring 2011 – Lecture 6
Benefits of ArcSDE
• Use of robust RDBMS environment
– Security, backup and recovery
– Scalability, Indexing
– Referential and data integrity
– Can access GIS attribute data at the db level via
SQL*Plus, OSQL, or in MS Access with ODBC
connection, etc.
– Link to data in existing RDBMS
– Supports long transactions and Views
– SDE administrators may be assisted by system
administrators and RDBMS administrators
EEOS 381 Spring 2011 – Lecture 6
Benefits of ArcSDE
• Spatial queries directly at SQL prompt if
RDBMS supports spatially-enabled data
types
– Oracle Spatial, DB2 Spatial Extender, Informix Spatial
DataBlade, SQL Server 2008 spatial data type
• Use C, Java API for custom app. dev.
• Fully integrated with ArcGIS
• Can batch data import/export and other
processes using Administrator Commands
EEOS 381 Spring 2011 – Lecture 6
Drawbacks of ArcSDE
• Requires separate purchase of RDBM$
– Need a DBA or be trained in your RDBMS software for
backups, tuning (require time, money, expertise)
• Can take a while to master intricacies,
work around errors
• May require re-working of legacy
applications that may not be broken *
• May require VBA/ArcObjects or other
programming skills to customize *
* - for ArcGIS/GDB in general
EEOS 381 Spring 2011 – Lecture 6
Types of ArcSDE
(ArcSDE GDBs are Scalable)
Enterprise Workgroup Desktop Geodatabase
Geodatabase Geodatabase (known as Personal SDE at 9.2)
Application Large-scale enterprise applications Small- to medium-sized Small teams or a single user who
Scenario departmental applications requires the functionality of a
multiuser geodatabase
Supported RDBMS DB2, Informix, Oracle, PostgreSQL, SQL Server Express SQL Server Express
SQL Server
Management ArcCatalog, RDBMS, ArcSDE ArcCatalog ArcCatalog
Interface command line
Storage Capacity Depends on the server 4 GB 4 GB
Licensing ArcGIS Server Enterprise ArcGIS Server Workgroup ArcGIS Engine, ArcInfo, ArcEditor
Availability
Supported OS Any platform Windows Windows
Platform
Number of Unlimited editors and readers 10 editors and readers 1 editor and 3 readers
Concurrent Users
Network Intranet and Internet Intranet and Internet Desktop and local network use
Application
Differentiating Supports versioning and multiuser Supports versioning and Supports versioning
Characteristics editing; Supports spatial types; multiuser editing
integration with enterprise IT
NEW @ 9.2
EEOS 381 Spring 2011 – Lecture 6
Accessing ArcSDE
Enterprise
Personal/Desktop
and Workgroup
EEOS 381 Spring 2011 – Lecture 6
Accessing ArcSDE
How to connect to read-only data in
Enterprise ArcSDE in the labs: lassen-pea See
note
below
• Double-click "Add Spatial Database
Connection" from the "Database
Connections" in ArcCatalog or ArcMap.
• Enter the parameters as shown in the
image at right.
• Note: the Password is the same as the User
Name – datareader
• To connect to your data (to edit), you would
enter your username and password
• Click Test Connection. If the “Connection
Succeeded” message appears, it worked.
• Click OK.
These parameters get saved to a .sde file in your
profile (on the C: drive). You can copy this file to H:
for use on any PC.
You can use the datareader@lassen-pea connection in If Service not found, use 5151 instead of esri_sde
S:\ge381_s11\
EEOS 381 Spring 2011 – Lecture 6
ArcSDE Feature Classes
• GDB “container” for vector data
– One geometry type (point, line, polygon, annotation, etc.) per
feature class, and attributes
– Owned by RDBMS users (i.e. Oracle accounts, like MGISDATA)
• Stored as series of tables in the RDBMS
– Joined at query time so that the client (i.e. ArcCatalog) sees one
object (layer) in the geodatabase
– One row is one feature (single or multi-part)
• Spatial column identifies geometry
– “SHAPE” field
– in RDBMS, actual coordinates stored in BLOB (binary long object) or
long raw formats
shape + attributes = feature
EEOS 381 Spring 2011 – Lecture 6
ArcSDE Feature Classes
• Types of storage
– ST_GEOMETRY
• Base table with attributes and spatial
column, and spatial index
• Default at version 10
– SDELOB (binary geometry type)
• Business (attributes), F (spatial), and S
(spatial index) tables
For more details see:
http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#/Feature_class_storage/002n0000007m000000/
EEOS 381 Spring 2011 – Lecture 6
Feature class tables in the RDBMS
(SDELOB storage)
• Business table
– stores attributes
– name in RDBMS is feature class name (e.g.
TOWNS_POLY), as seen in ArcGIS. Its actual
appearance depends on the RDBMS:
• Oracle: OWNER.TABLENAME
– Ex: MGISDATA.TOWNS_POLY
• SQL Server: DATABASE.OWNER.TABLENAME
– Ex: SDE.MGISDATA.TOWNS_POLY
EEOS 381 Spring 2011 – Lecture 6
Feature class tables in the RDBMS
(SDELOB storage)
• Feature table (“F” table)
– stores geometry in binary column (X,Y,Z,M
values), plus envelope (bounding rectangle)
for each feature, area & length
– named F in RDBMS (layer_id is
primary key in SDE.LAYERS table)
– one-to-one relationship between business and
F table, via unique feature identifier
(“OBJECTID”, always indexed)
EEOS 381 Spring 2011 – Lecture 6
Feature class tables in the RDBMS
(SDELOB storage)
• Spatial index table (“S” table)
– stores grid tiles and envelope (X/Y extent of
each tile)
– named S in RDBMS
– one-to-many relationship between F and S
table
– used during spatial searches (pan/zoom) for
optimum data retrieval
EEOS 381 Spring 2011 – Lecture 6
Spatial Indexes
• Clients use spatial filter to reduce
query results and speed up data
retrieval
– Ex.: Only fetch visible features for display
• ArcSDE uses spatial index to reduce I/O
– Eliminates need for full table scan
– Based on standard feature of RDBMS
• Format of the spatial index is
determined by the RDBMS being used
– Grid tile or R-tree (Oracle Spatial) structure
EEOS 381 Spring 2011 – Lecture 6
Spatial Indexes
• ArcSDE for Oracle uses grid tile structure
– Spatial index built by applying a grid
to the feature class
– ArcSDE records which features fall
within each grid cell in an index
table (“S” table), based on feature
envelope
– A feature that falls within many cells
is listed in each
– Grid cells with no data are not listed
in table
– A layer may have 1 to 3 index grids,
though usually one is sufficient
– When you create a vector feature
class, ArcGIS automatically
determines the optimum grid cell The feature class is overlaid by grid cells
size (in the units of the data, e.g. to create the spatial index.
feet, meters) and the number of
grids.
EEOS 381 Spring 2011 – Lecture 6
Feature class tables in the RDBMS
(SDELOB storage)
• “Adds” table (“A” table)
– stores added features during ArcMap
versioing edit session
• “Deletes” table (“D” table)
– stores deleted features during ArcMap
versioning edit session
aka Delta (change) tables
Named A and D
(registration_ID is primary key in SDE.TABLE_REGISTRY table)
EEOS 381 Spring 2011 – Lecture 6
ArcSDE Feature Classes
• ArcSDE manages integrity of tables (i.e.
when a layer is renamed, deleted, edited)
– users should never alter these tables‟ schemas
• i.e. add columns to layers in ArcCatalog or
ArcMap only !!
– You CAN use SQL*Plus or MS Access to edit
business table attributes (and to add rows to
non-feature class tables – but be careful!
EEOS 381 Spring 2011 – Lecture 6
ArcSDE Feature Classes
• Additional column indexes may be built
on attributes in business table
Improves
performance
when using
joins, relates,
and relationship
classes.
EEOS 381 Spring 2011 – Lecture 6
Loading Data into ArcSDE
• Use ArcToolbox Conversion Tools > To Geodatabase
• Right-click spatial database connection and choose Import
– Supported data types or XML docs
• Right-click existing SDE layer and choose Load > Load
Data…
• Create new empty FC with desired schema (can import
from a table) and Load in features from any data source
• Right-click non-SDE layers and choose Export > To
Geodatabase
• Use SDE commands
– shp2sde, cov2sde, tbl2sde (for tables)
• Use special tools/dialogs for labels and annotation
EEOS 381 Spring 2011 – Lecture 6
After Loading Data into ArcSDE
• Right-click and
– Assign privileges to data – way to control access
• Enter db user or role
• Check SELECT, UPDATE, INSERT, DELETE
– Analyze
• Updates DBMS statistics
• Check/clear components to analyze
• Rename layers?
– Loaded data named the same as existing data will
have “_1” in new name
• Take a look at the data!!!
EEOS 381 Spring 2011 – Lecture 6
Raster Data in the RDBMS
>> ArcSDE/GDB raster layers are known as “raster datasets”
EEOS 381 Spring 2011 – Lecture 6
Raster Data in the RDBMS
• Benefits
– RDBMS security, data management and
retrieval
– Common data format
– Supports large seamless images (mosaics)
or raster catalogs
– Compression
• LZ77 lossless or lossy
• JPEG and JPEG 2000 lossy
– Pyramids stored in database for improved
display performance
EEOS 381 Spring 2011 – Lecture 6
Raster Data in the RDBMS
• Loading
– ArcCatalog / ArcToolbox (all supported formats)
– Use sderaster command (for 1 to 3-band TIFF,
BSQ, or ArcSDE raster)
– Then:
• Build Pyramids
• Calculate Stats
• Analyze
Pyramids
enable fast
display at any
scale
EEOS 381 Spring 2011 – Lecture 6
Raster Data in the RDBMS
• SDE.RASTER_COLUMNS table …
– Stores information on every raster dataset
in the database, one entry per dataset
– Each layer has unique ID -
RASTERCOLUMN_ID - assigned by ArcSDE
For more details see:
http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#/Raster_storag
e_types_in_an_ArcSDE_geodatabase/002n0000006v000000/
EEOS 381 Spring 2011 – Lecture 6
Raster Data in the RDBMS
• … and a series of many tables
– Raster layer Business table
(OWNER.IMAGE_NAME – as seen in ArcGIS)
• Link between supporting tables and RASTER_COLUMNS table
– Raster layer Block Table
(SDE_BLK_)
• Stores actual pixel data
– Raster layer Metadata Table
(SDE_RAS_)
• contains raster description
– Raster layer Band Table
(SDE_BND_)
• Information about each raster band
– Raster layer Auxiliary table
(SDE_AUX_)
• Stores colormaps and statistics
EEOS 381 Spring 2011 – Lecture 6
ArcSDE Uses Client/Server Model
• All data stored in RDBMS
accessed over a TCP/IP network
• All data is retrieved through SQL
(Structured Query Language)
queries
– SELECT statements fetch data
(see pages 259-260 in textbook)
• Query filters limit the rows
returned
– Attribute and Spatial
• Clients display data
• Two connection methods
– Application Server
– Direct Connect
EEOS 381 Spring 2011 – Lecture 6
ArcSDE Application Server Connection
• Traditional ArcSDE connection
method ArcGIS
– Available for all supported • Link between application and database
RDBMS • Processes client requests
• Sends data from client to server TCP/IP
• GIS client requires no additional
• Updates & maintains ArcSDE metadata network
• Active until user disconnects
software
• Server requires ArcSDE instance
5151
– giomgr spawns one dedicated
gsrvr process per connection, ArcSDE
using RDBMS authentication gsrvr
• Performance considerations RDBMS
server
– Decreases client load • Listens for, monitors, and
maintains connections,
– Decreases network load spawns gsrvr processes
ArcSDE
– Increases server load Data
giomgr
EEOS 381 Spring 2011 – Lecture 6
ArcSDE Direct Connect
• Client connects directly to RDBMS
• Client does its normal job AND performs ArcGIS
function of the gsrvr, using a software
client
library called a Direct Connect driver (with Direct Connect
Driver)
• No ArcSDE instance used
• No gsrvr or giomgr processes required
on server
RDBMS
• Performance considerations
– Increases client load
– Increases network load
– Decreases server load (most appropriate
for robust clients on hearty computers)
For more details start with:
http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#/What_is_a_direct_connec
tion_to_a_geodatabase_in_Oracle/002n00000035000000/
EEOS 381 Spring 2011 – Lecture 6
Services File
• Stores port number (5151) used by ArcSDE
for communication between client and RDBMS
Add the following line:
esri_sde 5151/tcp
to the SERVICES file in
C:\WINDOWS\SYSTEM32\DRIVERS\ETC
or C:\WINNT\system32\drivers\etc
or other similar location.
EEOS 381 Spring 2011 – Lecture 6
SDE.DBTUNE Table
• RDBMS table (owned by SDE user) that stores storage
tuning parameters in an enterprise ArcSDE geodatabase
• Based on keywords
– “DEFAULTS” used for all feature classes loaded without keyword
specified
– Different keywords can be set up by the SDE administrator for
vector data, raster data, topology, and for different users and
editors
– Control where data are stored - i.e. which tablespace (Oracle) or
file group (SQL Server) for feature tables, indexes.
– If you want users to be able to write to (i.e., store data in) certain
parts of a database, the SDE administrator would set up a
keyword (like ##STUDENTS), and in ArcGIS dialogs that have a
dropdown or textbox to specify a configuration keyword, the user
would enter STUDENTS.
EEOS 381 Spring 2011 – Lecture 6
ArcSDE Repository
• Administrative information
– Feature class name
– Unique feature class ID, etc. …
• AKA “ArcSDE system tables”
sde.raster_columns
sde.table_registry A few of the
sde.layers many tables
LAYER_ID owned by the
TABLE_NAME
... sde user
See system tables diagram at:
http://help.arcgis.com/en/arcgisdesktop/10.0/help/002n/pdf/sdesystables_diagram.pdf
Full details at:
http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#/ArcSDE_geodatabase_sys
tem_tables/002n0000008m000000/
EEOS 381 Spring 2011 – Lecture 6
ArcSDE Administration Tools
• Command-line utilities for managing the ArcSDE
server
– Executed at operating system prompt
– May be used remotely
– Command syntax found in the ArcSDE Developer Help
• See
http://help.arcgis.com/en/geodatabase/10.0/admin_cmds/support_files
/admincmdref.htm
– Benefits
• Easy to format
• Easy to debug
• Reusable
• Record of work (can write output to log files)
• Unattended execution (can batch)
EEOS 381 Spring 2011 – Lecture 6
ArcSDE Administration Tools
• Example: the sdemon command
– Purpose: ArcSDE server monitor, used to check
connection statistics. The sytax is:
sdemon -o info -I [-I
]
– Required parameter sdemon -o info
– Optional parameter [ ]
– Substitute a value
– Choose a value from list for the
argument:
-I
• Others: sderaster, cov2sde, shp2sde,
sdeexport, sdeimport, sdelayer, sdetable,
...
EEOS 381 Spring 2011 – Lecture 6
Versioning
• ArcSDE Geodatabase mechanism to allow multiple users
to simultaneously edit the same database, including the
same layers and features, without explicitly applying locks
to prohibit other users from modifying the same data
• Part of “multi-user editing” capability of SDE
geodatabases
• No need to extract or make copies of data for editing
EEOS 381 Spring 2011 – Lecture 6
Versioning
• What is a “version”?:
– “In databases, an alternative state of the database
that has an owner, a description, a permission
(private, protected, or public), and a parent version.
Versions are not affected by changes occurring in
other versions of the database.”
- From ESRI GIS Dictionary
– You can think of a version as your own “doorway” to
the database, allowing you to make changes that
don‟t affect the database as a whole.
– Also see ESRI Help:
• http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#/What_
is_a_version/00270000000q000000/
• http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#/A_quic
k_tour_of_versioning/00270000000r000000/
EEOS 381 Spring 2011 – Lecture 6
Versioning
• Use versioning to:
– Manage alternative engineering designs
– Solve complex what-if scenarios without
impacting the production database
– Create point-in-time representations of the
database
– Conflict resolution dialog allows DBA to
choose proper version
EEOS 381 Spring 2011 – Lecture 6
Versioning
• Versions are not copies of the database or
layers
– Only store edits made to database in A and D tables
• Versions are named
– default version (always present) is SDE.DEFAULT
– syntax: OWNER.VERSION_NAME
– AKA a named “state” of the database
• Maintain parent-child relationships (see chapter
7 in Modeling Our World and chapter 10 in Building A
Geodatabase)
EEOS 381 Spring 2011 – Lecture 6
Versioning
• Isolates user's work across multiple edit
sessions, allowing the user to edit without
locking features in the production version or
immediately impacting other users.
• Supports undo/redo capability
• Multiple users can access a version
• A user may access multiple versions
– What the user can do is based on version
permissions
• Contains access to all the datasets in the
geodatabase
EEOS 381 Spring 2011 – Lecture 6
Versioning
• Versions have permissions:
– Public - any user may view the version and
modify features
– Protected - Any user may view version, only the
owner may edit
– Private - Only the owner may view the version
and modify features
• Notes:
– Version owner can rename, delete, change access
– SDE user can see and delete all versions
regardless of their permissions
EEOS 381 Spring 2011 – Lecture 6
Versioning
• How tables react to edits:
– Insert (add) feature
• record (OBJECTID) added to A table
– Delete feature
• record (OBJECTID) added to D table
– Update feature
• records (OBJECTIDs) added to A and D
tables
EEOS 381 Spring 2011 – Lecture 6
Versioning Process Step 1 – Data Owner
• In ArcCatalog:
1. Register data with geodatabase, if necessary
2. Register data as Versioned (makes data editable)
• A & D tables added to feature class:
– A stores adds
– D stores deletes
3. Grant SELECT, UPDATE, INSERT, DELETE privileges
to all editors
To register an object as versioned,
right-click it in ArcCatalog and choose
„Register As Versioned…‟. You must be
connected as the owner of the dataset.
EEOS 381 Spring 2011 – Lecture 6
Versioning Process Step 2 - Editor
1. Create version, set permission (ArcCatalog)
2. Change version in your spatial database
connection and add feature class (or feature
dataset) to ArcMap
3. Make and save edits in ArcMap
4. From Versioning Toolbar in ArcMap:
– Reconcile with parent (other edits in parent seen
by child)
– Post changes to parent (changes in child seen by
parent)
• parent owner needs to do this if parent version is not
„public‟
– parent makes version of child and posts
EEOS 381 Spring 2011 – Lecture 6
Versioning
SDE.DEFAULT
Process – Editing (PROTECTED)
SCOTT.OS_DBA
(Protected)
MTRUST.MYEDITS JKERRY.MYEDITS
(protected) Layer edited
and saved
(protected)
SCOTT.MTRUST_QA SDE.READY_FOR_DEFAULT
(protected)
EEOS 381 Spring 2011 – Lecture 6
Versioning Process Step 3 – SDE user
1. Compressing the Database
– Done as SDE user, with Compress button added to a toolbar from
Customize box in ArcCatalog, or with ArcToolbox tool
– Moves records in A & D tables into base (business, F, & S) tables
– Removes all redundant rows and states not referenced by a
version
– Improves performance
– Two types:
• Full compress: When editing is done and all reconciling and posting is
complete, after deleting all versions
• Partial compress: done anytime, but locks may prevent deletion of
certain states
2. Analyze data after compression
• Note: “Compact” is procedure for PGDBs
EEOS 381 Spring 2011 – Lecture 6
Versioning Process
SDE.DEFAULT
- Compressing (PROTECTED)
Compress Geodatabase
SCOTT.OS_DBA Start the
(Protected) process
all over
again
MTRUST.MYEDITS JKERRY.MYEDITS
(protected) Layer edited
and saved
(protected)
SCOTT.MTRUST_QA SDE.READY_FOR_DEFAULT
(protected)
EEOS 381 Spring 2011 – Lecture 6
Non-versioned Editing
• Editing of source data directly
– Features and attributes
• The last saved edit is final
• No ability to undo/redo changes
– The only way to “undo” back to last edit is to stop editing
without saving changes
• The object (feature class or table) does not have to be
registered as versioned)
To “turn on” non-versioned editing, in
ArcMap, go to the Editor toolbar, click
on the Editor menu dropdown, and
choose Options…. Then, in the
Versioning tab, uncheck the „Edit a
version…” checkbox.
EEOS 381 Spring 2011 – Lecture 6
Versions
Version tree schematic
showing database states
(saved edits, represented
by the circled numbers)
for a power plant
geographic database
EEOS 381 Spring 2011 – Lecture 6
Versions
Version Reconciliation based on a
conflict. The user who posts the data
to the DEFAULT or other admin-type
version would determine which
version is accepted.
Which version is posted?
EEOS 381 Spring 2011 – Lecture 6
Versions
Click this tab
Then click
on this icon
The free Geodatabase
Toolset add-on to
ArcCatalog allows one
to see the states and
versions in an
enterprise ArcSDE
geodatasbase.
Read details and download from
http://www.esri.com/software/arcgis/extensions/gdbt/index.html
EEOS 381 Spring 2011 – Lecture 6
GDB Replication
• Allows you to create copies of data across two or more
geodatabases such that changes to the data may be
synchronized.
• Requires ArcInfo or ArcEditor
• For more information, start with “Understanding
distributed data” in ArcGIS Help for full details:
http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#/Unde
rstanding_distributed_data/002700000020000000/
EEOS 381 Spring 2011 – Lecture 6
GDB Archiving
• Provides the functionality to record and access changes
made to all or a subset of data in a versioned
geodatabase.
• The mechanism for capturing, managing, and analyzing
data change.
• See “Geodatabase archiving” for more details:
http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#/Geod
atabase_archiving/002700000045000000/
EEOS 381 Spring 2011 – Lecture 6
Views
• A “virtual table” in a database that displays certain
information in the database, based on a view definition
• Not a table itself; the definition is stored and the view
appears as a table when accessed by a user
• Advantages
– Can limit rows (use “where clause”) and include only
certain fields
• Simplicity and security
– Can assign alias (more intuitive) field names
– Can include joins to other tables
When SHAPE field is included in an SDE view, the view
appears as an ArcSDE Feature Class (“Spatial view”)
Use the sdetable –o create_view admin command
See: http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#/What_is_a_view/002n00000027000000/
EEOS 381 Spring 2011 – Lecture 6