Attribute Data

Title

The name of the data table.

Records

The OBJECTID of the rows; numbered 1, 2, 3, …

Field

The name of the data column.

Field defintions

Control the type of data that can be stored in a field. 

Attribute table

Stores attributes of map features. Associated with spatial data layer. Has special fields for spatial information.

Standalone table

Stores any tabular data. Not associated with spatial data. OID instead of FID.

Database management systems

Dedicated systems for managing tables of data. Provide data management for agencies, universities, companies, etc. Designed for multi-user environments with enhanced security needs. Focus on data ables with tools for queries, reporting, graphing, etc. 

Flat file DBMS

Stores data as rows of information in files. Simple and robust. Inefficient for search and query.

Hierarchial DBMS

Stores data in multiple tables. Tables have defined parent-child relationships. Pre-set hierarchy of table repationships designed for specific queries. Very efficient for specific quetries. Range of queries limited by structure.

Relational DBMS

Stores data in multiple tables. Table relationships are defined as needed. Very flexible. Ideal for open-ended applications when queries not known beforehand. Most common type used in GIS applications.

Joining tables

Allows two tables to be used as a singel table. Records are linked using a common field. The target table recieves additional information and the join table prvides the additional information.

Key

A common field is also known as a…

Target table

Recieves the additional information in a join. 

Join table

Provides the additional information in a join.

Multiple joins

More than two tables may be joined to a target table.

One-to-one joins

One record in the join table matches one record in the target table.

Cardinality

How many join records match each target record. 

Many-to-one join

One record in the join table matches many records in the target table. The join record is repeated as needed to fill out the target records.

One-to-many join

Many records in the join table match one record in the target table. Cannot be joined, and are instead related.

Relate

When tables remain seperate but are linked together so that a selection in one table can be used to select the linked records in the other table.

Rule of Joining

Each record in the target table must match one and only one record in the join table (one-to-one and many-to-one).

Many-to-many cardinality

Multiple records in one table match multiple records in another table. Can be related, but are not usually satisfactorily treated in GIS.

Summary statistics tool

Used to calculate statistics for one or more fields. Results are stored in a new table. 

Case field

Can be used to group features first.

Fields

Specific types available and must be defined before use. Once defined, they cannot be changed.

No more than 13 characters

Use only letters and numbers

Must start with a letter

Field naming rules:

Short, long, float, double, text, date

ArcGIS field data types:

Short field type

Integers stored as 2-byte binary numbers

Range of values -32,000 to +32,000

Examples: 255 and 12001

Long field type

Integers stored as 10-byte binary numbers

Range of values -2.14 billion to +2.14 billion

Examples: 156000 and 457890

Float field type

Floating-point values with 8 significant digits in the mantissa

Examples: 1.289385e12 or 1.5647894e −02

Double field type

Double-precision floating-point values with 16 significant digits in the mantissa

Example: 1.12114118119141e13

Text field type

Alphanumeric strings

Examples: ‘Maple St"‘ and ‘John H. Smith’

Date field type

Date/time format for calendar dates and times

Examples: 07/12/2008 and 10/17/1963 13:24:06

Calculate Field tool

Used to enter an expression to calculate new values for a field in a table.