Station_Comment 
Logical Entity Name  Station_Comment 
Default Table Name  Station_Comment 
Definition  Comments for a station 

Station_Comment Attributes 
Attribute/Logical Rolename  Domain  Datatype  NULL  Definition 
net(PK)(FK)    VARCHAR(8)  NO  Unique network identifier. This character string is the name of a seismic network 
sta(PK)(FK)    VARCHAR(6)  NO  Station code. This is the common code-name of a seismic observatory. Generally only three or four characters are used 
ondate(PK)(FK)    DATE  NO  This attribute denotes the start date 
comment_id(PK)(FK)    NUMERIC(8, 0)  NO  The comment code key of the associated Comment Description Dictionary 
offdate    DATE  YES  This attribute denotes the end date 
comment_level    NUMERIC(8, 0)  YES  The numeric value (if any) associated with the Units of comment level in the same Comment Description Dictionary. Together, this numeric value, its units, and the Description of comment of the associated Comment Description, all describe a comment for the station/channel 
lddate    DATE  YES  Load date. Date and time that the record was created or last modified, in Oracle date datatype 

Station_Comment Keys 
Key Name  Key Type  Keys 
StC00  PrimaryKey  net, sta, ondate, comment_id 

Station_Comment Relationships 
Parent Relationships: 
Entity Name  Type  Cardinality  Business Name  VerbPhrase  InversePhrase  Foreign Keys  Is Supertype 
D_Comment  Identifying  One To Zero or More        comment_id  NO 
Station_Data  Identifying  One To Zero or More        net, sta, ondate  NO 
Child Relationships: 
Entity Name  Type  Cardinality  Business Name  VerbPhrase  InversePhrase  Foreign Keys  Is Subtype 

Station_Comment Check Constraints 
Check Constraint Name  CheckConstraint