Can anyone see why I receive this null error? see code below

Error Executing Database Query.
[Macromedia][SequeLink JDBC Driver][ODBC Socket][Oracle][ODBC]
[Ora]ORA-01400: cannot insert NULL into ("user"."BID_LIST"."PRJ_ID")

<cfif IsDefined("form.gridEntered")>
<cfgridupdate grid = "FirstGrid" datasource= "abcd" tableName =
"GOOD_LIST" keyOnly = "no" >
</cfif>

<cfquery name="myqry" datasource="#DATASOURCE#">
SELECT prj_ID, ADDA, ADDADESC, ADDINDEX
FROM GOOD_LIST
WHERE (PRJ_ID = #URL.PRJID#)
</cfquery>


<!---
************************************************** ************************************************** ***
--->
<body bgcolor="#f6f6f5">
<i>You can update the Alt value, and Description for this project.</i>
<!--- The cfform tag must surround a cfgrid control. --->
<cfform action = "#CGI.SCRIPT_NAME#?PRJID=#URL.PRJID#" format="flash">
<CFGRID NAME="FirstGrid" WIDTH="875"
QUERY="myqry" INSERT="Yes"
DELETE="Yes" SORT="Yes"
FONT="Tahoma" BOLD="No" ITALIC="No"
APPENDKEY="No" HIGHLIGHTHREF="No"
GRIDDATAALIGN="LEFT" GRIDLINES="Yes"
ROWHEADERS="Yes" ROWHEADERALIGN="LEFT"
ROWHEADERITALIC="No" ROWHEADERBOLD="No"
COLHEADERS="Yes" COLHEADERALIGN="LEFT"
COLHEADERITALIC="No" COLHEADERBOLD="No"
SELECTCOLOR="##bcfeff" SELECTMODE="EDIT"
PICTUREBAR="No" INSERTBUTTON="To insert"
DELETEBUTTON="To delete" SORTASCENDINGBUTTON="Sort ASC"
SORTDESCENDINGBUTTON="Sort DESC" >

<CFGRIDCOLUMN NAME="PRJ_ID" SELECT="no" DISPLAY="no">
<CFGRIDCOLUMN NAME="ADDINDEX" DISPLAY="NO" >

<CFGRIDCOLUMN NAME="ADDA" HEADER="Estimate"
HEADERALIGN="LEFT" DATAALIGN="LEFT" width="100"
BOLD="Yes" ITALIC="No"
SELECT="yes" DISPLAY="Yes"
HEADERBOLD="No" HEADERITALIC="Yes">

<CFGRIDCOLUMN NAME="ADDADESC" HEADER="Description"
HEADERALIGN="LEFT" DATAALIGN="LEFT" width="150"
BOLD="Yes" ITALIC="No"
SELECT="Yes" DISPLAY="Yes"
HEADERBOLD="No" HEADERITALIC="Yes">

</CFGRID>

<cfinput type="submit" value="Save" name="gridEntered" >
</cfform>

</body>