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TransCAD

Managing Data Tables

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Create a New Table

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Add a field

Delete a field

Change the field order

Change a field name

Use a display name

Change a field type

Change a field width

Change the number of decimals

Set a default value in new records

Change a field format

Change a field description

Index a field

Change the aggregation method

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Adding Records to a New Table

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Adding Records to a New Table

Adding a Fixed Number of Records– If you know how many records you want to store in

the new table, you can tell TransCAD to add that number of blank records to the table.

Adding Matching Records– Use this option when you want to store additional

columns of information about records or map features in a new table. The Matching Records option automatically adds one matching record for each record or feature in the original dataview.

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Adding Records to a New Table

Adding a Record for Each Unique Value of a Field– Use this option when you want to create a

lookup table that adds new information to a map layer or dataview. To use this option, you must choose:

• The map layer or dataview you want to examine.

• The field whose values you want to use. TransCAD adds this field to the new table.

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Modify the Structure of a Table

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Working with Codes

Often a database will contain shorthand codes that have a particular meaning. Using codes saves space because long character strings are replaced with shorter codes.

To replace shorthand codes with descriptive text, you create a lookup table and attach it to the original table. A look up table is simply a table that contains the field names, the shorthand codes, and the descriptive text you eant to see displayed.

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Attach Codes

Lookup Table – All of the column data type has to be

character as well as the column contains codes

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Double Click

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Create a Lookup Table From a Dataview

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Create a New Table from a Dataview

Marking Column

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Creating a Table from an Excel File

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About Dictionary Files

Tables in fixed-format text, fixed-format binary, and comma- and tab-separated text format require an additional file called the dictionary file. The dictionary file serves as a header and tells TransCAD where to look in the data file for the different fields of data.

When you create a table in one of these formats, TransCAD automatically creates the dictionary file.

Dictionary files have the same file name as the data file and an extension of:– .DCT for a fixed-format text

file

– .DCC for a comma- or tab-separated text file

– .DCB for a fixed-fromat binary file