Data Schema Flashcards
• Identify how data is stored and managed in tables, records, and fields • Recognize the relationship between base, parent, and child tables • Evaluate the differences between core and custom tables • Use the tools provided to navigate table types and schema maps
Where to navigate to modify the record number format?
System Definition > Number Maintenance
Where to navigate to access tables?
System Definition > Dictionary
System Definition > Tables
System Definition > Tables & Columns
What is inside the Dictionary module?
Records for every table and field in the system
Table records are identified as a Collection type
What is inside the Tables module?
A record for each table in the DB
What is inside the Tables & Columns module?
All the tables in the DB
Selecting a table name displays its contents
Where to navigate to modify a table or a field attribute?
System Definition > Dictionary
How are records uniquely identified in the system?
Records are identified with a sys_id:
a globally unique ID of 32 characters
What is stored in fields?
Actual data
What are examples of different field types?
- Choice
- Date / Time
- Journal
- Reference
What are 3 key attributes of a field?
- Field name (stored in the system)
- Field label (user-friendly name)
- Field data (data stored in the field)
What is stored in a Reference field?
The sys_id of a record that lives in another table
How are Reference fields identified?
With the Reference lookup icon (magnifier)
What field type must we use in order to refer to records on any table?
Document ID element type
What are the 4 table relationships in ServiceNow?
- One-to-Many
- Many-to-Many (think software vendors and products)
- Database Views
- Extensions
What are the 3 One-to-Many relationship fields?
- Reference fields (Caller field on Incident table)
- Glide List (Watchlist field on Incident table)
- Document ID fields (Document field on the Translated Text table)
Which table relationship can be used for reporting on data stored in different tables?
Database Views (which are read-only)
Which tables are useful when working with many-to-many relationships?
- sys_collection
- sys_m2m
What fields are automatically created when a stand alone table is created?
The global default fields
When can we extend a table?
When we create the table
Are all tables extensible?
No
Where to navigate to add a table label for an extended table?
System Definition > Language File
How to make a table extensible?
Select the Extensible checkbox on the table record
Which feature do we use to define a field on a child table differently from the parent table?
Dictionary overrides
What is a core table?
A table that comes with the system (like Incident)
What is a base table?
A table that is not extending another table (like Task)
If a table is created in a scoped application, what is the prefix in the table name?
x_
If a table is created in the global scope, what is the prefix in the table name?
u_
What is the purpose of the schema map?
Provide a graphical representation of the tables related to a specific table
- Use it to see which fields are inherited from parent table and which fields originate on the child table, and to look up field types
How can we filter the table relationships in the schema map?
Based on reference or extension classes
- red: show referenced tables
- orange: show referencing tables
- green: show extended tables
- blue: show extending tables
Schema map is available to which roles?
- admin
- personalize_dictionary
How to generate a schema map?
- System Definition > Tables and Columns
- Select a table
- Press Schema Map button
Lab - Which button must be selected on the Table form in order to have a module created
Create module
