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TransCAD. Managing Data Tables. Create a New Table. 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
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TransCAD Managing Data Tables
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
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.
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.
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.
Attach Codes Lookup Table – All of the column data type has to be character as well as the column contains codes
Create a New Table from a Dataview Marking Column
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 About Dictionary Files