ArcGIS Difference Between SDE FGDB PDGDB

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Types of geodatabases

Release 9.3

The geodatabase is a "container" used to hold a collection of datasets. There are three types:

1. File GeodatabasesStored as folders in a file system. Each dataset is held as a file that can scaleup to 1 TB in size. The file geodatabase is recommended over personal geodatabases.

2. Personal GeodatabasesAll datasets are stored within a Microsoft Access data file, which is limitedin size to 2 GB.

3. ArcSDE GeodatabasesSt ored in a relational database using Oracle, Microsoft SQL Server, IBM

DB2, IBM Informix, or PostgreSQL. These multiuser geodatabases require the use of ArcSDE and

can be unlimited in size and numbers of users.

Comparing the three types of geodatabases

Key

characteristics

ArcSDE

ge odatabase File ge odatabase Personal ge odatabase

Description A collection of

various types of GISdatasets held as

tables in a relational

database

The recommended

native data format

for ArcGIS stored

and managed in arelational database

A collection of various

types of GIS datasets heldin a file system folder.

This is the recommended

native data format for

ArcGIS stored and

managed in a file system

folder.

Original data format for

ArcGIS geodatabasesstored and managed in

Microsoft Access data files.

This is limited in size and

tied to the Windows

operating system.

Number of Users Multiuser

Many readers and

many writers

Single user and small

workgroups.

Many readers or onewriter per feature dataset,

stand-alone feature class,

or table.

Concurrent use of any

specific file eventually

degrades for largenumbers of readers.

Single user and small

workgroups with smaller

datasets.

Some readers and one

writer.

Concurrent use eventually

degrades for large

numbers of readers.

Storage FormatOracle

Microsoft

SQL Server

IBM DB2

IBM

Informix

PostgreSQL

Each dataset is a separate

file on disk.

A file geodatabase is a file

folder that holds itsdataset files.

All the contents in each

personal geodatabase are

held in a single Microsoft

Access file (.mdb).

Size Limits Up to DBMS limits One TB for each dataset.

Each file geodatabase can

hold many datasets.

The 1 TB limit can be

raised to 256 TB for

extremely large imagedatasets.

Each feature class can

scale up to hundreds ofmillions of vector features

per dataset.

Two GB per Access

database.

Effective limit before

performance degrades is

typically between 250 and

500 MB per Accessdatabase file.


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Versioning

Support

Fully supported

across all DBMSs

includes cross-

database replication,updates using

checkout and check-

in, and historical

archiving

Only supported as a

geodatabase for clients

who post updates using

checkout and check-in andas a client to which

updates can be sent using

one-way replication.

Only supported as a

geodatabase for clients

who post updates using

checkout and check-in andas a client to which

updates can be sent using

one-way replication.

Plat forms Windows, UNIX,Linux, and direct

connections to

DBMSs that can

potentially run on

any platform on the

user's local network

Cross-platform. Windows only.

Security and

Permissions

Provided by DBMS Operating file system

security.

Windows file system

security.

DatabaseAdministration

Tools

Full DBMS functionsfor backup, recovery,

replication, SQLsupport, security,

and so on

File system management. Windows file systemmanagement.

Notes Requires the use of

ArcSDE technology

ArcSDE for SQL

Server Express

included with

ArcEditor

and ArcInfo

ArcGISEngine

ArcGIS

Server for

workgroups

ArcSDE for all other

DBMSs included with

ArcGIS Server for

enterprises

Allows you to optionally

store data in a read-only

compressed format toreduce storage

requirements.

Often used as an attribute

table manager (via

Microsoft Access).

Users like the string

handling for text

attributes.

Learn about creating geodatabases.

File geodatabases and personal geodatabases

File and personal geodatabases, which are freely available to all users of ArcView, ArcEditor, and ArcInfo, are

designed to support the full information model of the geodatabase. This includes topologies, raster catalogs,

network datasets, terrain datasets, address locators, and so on. File and personal geodatabases are designedto be edited by a single user and do not support geodatabase versioning. With a file geodatabase, it is

possible to have more than one editor at the same time, provided they are editing in different feature

datasets, stand-alone feature classes, or tables.

The file geodatabase was a new geodatabase type released in version 9.2. Its goals are to

Provide a widely available, simple, and scalable geodatabase solution for all users.

Provide a portable geodatabase that works across operating systems.

Scale up to handle very large datasets.

Provide excellent performance and scalability, for example, to support individual datasetscontaining well over 300 million features and datasets that can scale beyond 500 GB per file with

very fast performance.

Use an efficient data structure that is optimized for performance and storage. File geodatabases
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use about one third of the feature geometry storage required by shapefiles and personal

geodatabases. File geodatabases also allow users to compress vector data to a read-only format to

reduce storage requirements even further.

Outperform shapefiles for operations involving attributes and scale the data size limits way beyond

shapefile limits.

Personal geodatabases have been used in ArcGIS since their initial release in Version 8.0 and have used theMicrosoft Access data file structure (the .mdb file). They support geodatabases that are limited in size to 2

GB or less. However, the effective database size is smaller, somewhere between 250 and 500 MB, before the

database performance starts to slow down. Personal geodatabases are also only supported on the Microsoft

Windows operating system. Users like the table operations they can perform using Microsoft Access onpersonal geodatabases. Many users really like the text handling capabilities in Microsoft Access for working

with attribute values.

ArcGIS will continue to support personal geodatabases for numerous purposes. However, in most cases, we

recommend using file geodatabases for their scalability in size, significantly faster performance, and cross-

platform use. The file geodatabase is ideal for working with file-based datasets for GIS projects, for personal

use, and for use in small workgroups. It has strong performance and scales well to hold extremely large datavolumes without requiring the use of a DBMS. Plus, it is portable across operating systems.

Typically, users will employ multiple file or personal geodatabases for their data collections and access thesesimultaneously for their GIS work.

ArcSDE geodatabases

When you need a large multiuser geodatabase that can be edited and used simultaneously by many users,

the ArcSDE geodatabase provides a good solution. It adds the ability to manage a shared, multiusergeodatabase as well as support for a number of critical version-based GIS workflows. The ability to leverage

your organization's enterprise relational databases is a key advantage of the ArcSDE geodatabase.

ArcSDE geodatabases work with a variety of DBMS storage models (IBM DB2, Informix, Oracle, PostgreSQL,and SQL Server). ArcSDE geodatabases are primarily used in a wide range of individual, workgroup,

department, and enterprise settings. They take full advantage of underlying DBMS architectures to support

Extremely large, continuous GIS databases

Many simultaneous users

Long transactions and versioned workflows

Relational database support for GIS data management (providing the benefits of a relationaldatabase for scalability, reliability, security, backup, integrity, etc.)

SQL types for Spatial in all supported DBMS's (i.e., Oracle, SQL Server, PostgreSQL, Informix, and

DB2)

High performance that can scale to a very large number of users

Through many large geodatabase implementations, it has been found that DBMSs are efficient at moving in

and out of tables the type of large binary objects required for GIS data. In addition, GIS database sizes and

the number of supported users can be much larger than with file-based GIS datasets.

For information about the ArcSDE geodatabase architecture and how ArcSDE geodatabases leverage

relational database technology, see Architecture of the geodatabase.

ArcSDE provides long and short transaction management on the DBMS transaction framework

One of the primary roles for ArcSDE is to support the geodatabase versioning framework in each DBMS.

Quite frequently, an individual editing transaction in a GIS can involve changes to multiple rows in multiple

tables. For example, updating a parcel may require that you change the polygon's representation along with

changing the corresponding boundary lines and parcel corners. In addition, attribute records for each of these

features must be updated as well. This edit involves making changes to multiple records in many tables. In

these cases, users want to treat this collection of edits as a single transaction. When the changes arecommitted or rolled back, they are managed together as a unified operation.

At the same time, users want the ability to undo and redo individual edit operations within an edit session. Tofurther complicate this situation, the edits may need to be performed in a system that is disconnected from

the central, shared database.

Furthermore, during these specialized GIS data maintenance processes, the GIS database must remaincontinuously available for daily operations, where each user might have a personal view or state of the

shared GIS database.

The ArcSDE geodatabase supports the management and updates for these and many other datamanagement scenarios in a multiuser environment by using a method called versioning. Versioning is a

mechanism in which all database changes are recorded as rows in tables. For example, each time you update
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a value in a row, the old row is "retired" and a new, updated row is added.

In this way, ArcSDE technology manages such high-level, complex GIS transactions on the simple DBMS

transaction framework by storing change information as delta records in the database.

NOTE: This mechanism for maintaining records of all changes along with their metadata is the genesis ofthe term versioning.

ArcSDE uses metadata about versions to isolate multiple edit sessions, support complex transactions, share

replicas, synchronize contents across multiple databases, perform automatic archiving, and support historicalqueries.

See An overview of editing and maintaining data for more information.

How is ArcSDE technology included in ArcGIS?

In the past, ArcSDE was sold as a separate ESRI product. Starting with ArcGIS 9.2, ArcSDE technology hasbeen included as capabilities within ArcGIS rather than being offered as a separate product. ArcSDE

technology has been integrated into ArcGIS Desktop, ArcGIS Engine, and ArcGIS Server so that users can

scale their DBMS-based geodatabases across their organizations.

Beginning at ArcGIS 9.2, ArcEditor and ArcInfo have included the Microsoft SQL Server Express database free

of charge. These software products also include ArcSDE capabilities to support ArcSDE geodatabases in SQL

Server Express for up to three simultaneous desktop users.

Beginning with ArcGIS 9.3, ArcGIS Engine includes support for SQL Server Express free of charge. The

optional Geodatabase Update extension for ArcGIS Engine is required for ArcGIS Engine applications that edit

geodatabases. You can learn more about ArcGIS Engine in the book named What is ArcGIS 9.3?

Microsoft limits the use of SQL Server Express to one CPU (or Core within a Socket) and to utilize 1 GB of

RAM. The maximum database size for SQL Server Express is limited to 4 GB.

Within ArcEditor and ArcInfo, the ArcCatalog application provides the ability for you to fully administer and

manage ArcSDE geodatabases using SQL Server Express. This provides full ArcSDE geodatabase capabilities

for up to a few users at a time. You set up and manage these ArcSDE geodatabases within ArcCatalog. No

extra software or database administration expertise is required.

ArcGIS Server Workgroup also includes ArcSDE support for SQL Server Express. With this level of ArcSDE,

you can use SQL Server Express for up to 10 simultaneous Windows desktop users and editors (users of

ArcView, ArcEditor, ArcInfo, a custom ArcGIS Engine application, AutoCAD, MicroStation, and so on) plus any

number of additional server connections from Web applications. (Consult your license agreement for specificinformation on the number of connections for your implementation.)

For the workgroup server, you can use ArcEditor or ArcInfo to create, administer, and manage ArcSDE

geodatabases for SQL Server Express within ArcCatalog. No extra database administration expertise isrequired.

The ArcGIS Server Enterprise includes full enterprise ArcSDE technology with no limits. You can still run thetraditional ArcSDE technology for Oracle, SQL Server, PostgreSQL, IBM DB2, and IBM Informix. ArcSDE
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support in the Enterprise Server level can scale to databases of any size and number of users and runs oncomputers of any size and configuration. With ArcGIS Server Enterprise, you provide your own DBMS license

for this level of ArcSDE use. Choices include

Oracle

Microsoft SQL Server

IBM Informix

IBM DB2

PostgreSQLThe DBMS is typically administered and managed by a database administrator (DBA).

Summary points

You do not need to monitor and manage the use of your memory and CPUs for SQL Server Express.

The SQL Server Express software will automatically limit computer use to 1 GB RAM on a singleCPU and to a database size of 4 GB.

Unlike the Microsoft Access database, SQL Server Express performance does not degrade as the

database size approaches its maximum size limit (4 GB).

ArcSDE for SQL Server Express is included free as a part of ArcEditor and ArcInfo. If you choose to

install SQL Server Express, you can administer SQL Server Express databases using ArcCatalog.

When you install ArcGIS Server for Workgroups, you can install and use SQL Server Express andArcSDE. After installing SQL Server Express, you can use ArcCatalog in your ArcEditor or ArcInfo

seat to administer SQL Server Express databases for your Workgroup server.

These various levels enable users to take full advantage of ArcSDE geodatabases for any number of

users, large or small. This allows organizations to have one scalable data architecture that works

across their single-user systems up into their large enterprise systems.

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ArcGIS Difference Between SDE FGDB PDGDB