View source for MI Change Table Structure

== Introduction ==
TUFLOW requires the data attributes of each specific table to match those written with the .tcf command:<br>
<font color="blue"><tt>Write Empty MI Files </tt></font> <font color="red"><tt>==</tt></font> <tt>..\model\mi\empty</tt><br>
There are however a number of example of where modifying the names, types and order of these data attributes is useful. Examples include:
* Adding extra columns after the TUFLOW attributes, additional columns are ignored by TUFLOW. It can be useful add a comments field.
* Vertical Mapper inspections add additional columns, it may be desirable to remove or re-order these.
* Manipulate data into a TUFLOW format.

== Changing Data Attributes==
To change the data attributes of a table, use the menu item ''Table >> Maintenance >> Table Structure''.  When prompted select the table that you wish to modify. This will bring up a list of the data fields, the type of data (Character, Float [numeric], Integer...). Within this interface additional attributes can be added, removed, re-ordered and the data type/length can be changed.<br>
In the image below an additional data field with the name "Comments" has been added below the standard 1d_nwk attributes, this is a character field and can be used to store strings up to 250 characters in length. This field is ignored by TUFLOW and is an excellent place to store comments.<br>
In the second image, the ''Elevation'' column in a 2d_Zpt removed, it has been replaced by ''DEM_M01_1'' which was inspected using Vertical Mapper (see <u>[[Tute_M01_Inspect_Zpts_MI_Vertical_Mapper | Tutorial Module 1, Vertical Mapper]]</u>.<br>
'''WARNING''' Removing data fields can <u>not</u> be undone.
[[File:MI Table Structure.png|frame|none|1d_nwk Table Structure With Additional "Comments" Attribute]]
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[[File:Tute M01 Inspect Zpts MI TableStructure.png|frame|none|2d_Zpt table with the "Elevation" attribute removed]]