Import sets key concepts

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  • Updated July 31, 2025
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    Summary of Import Sets Key Concepts

    Import sets in ServiceNow provide a staging area for records imported from external data sources before they are transformed and loaded into target tables such as Incidents or Users. They facilitate controlled data import and transformation, ensuring data consistency and preventing duplicate records by skipping matches in the instance. Import sets operate with the System user and cannot write to encrypted fields.

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    It is important to avoid importing extremely large data chunks at once to prevent system delays or outages.

    Key Concepts and Terminology

    • Import Set Table: Auto-generated tables that temporarily hold imported data; columns are created based on input data and should not be manually altered to maintain cleanup integrity.
    • Data Source: Defines the origin of import data, such as files, databases, or LDAP directories.
    • Transform Map: Defines field-to-field relationships between import set tables and target tables to guide data transformation.
    • Transformation: The process of converting and moving data from the import set table to the target table based on transform maps.
    • Robust Import Set Transformer: An advanced tool that separates transformation and processing, allowing flexible ETL operations to multiple target tables.
    • Foreign Record Insert: Updates to reference tables during import (e.g., updating a user record when importing incident data).
    • Coalesce: A feature that allows updating existing records in the target table if matching values exist, otherwise creates new records.

    Supported Import Formats and Data Sources

    ServiceNow supports importing data from various file formats including CSV, Excel (XLS/XLSX), XML, and JSON, each with specific formatting requirements to ensure successful import.

    External data sources supported include JDBC databases, LDAP directories, OIDC, and REST endpoints (via Integration Hub), all requiring valid transform maps. Custom imports can be handled via scripts with transform maps.

    Transform Maps vs. Robust Import Set Transformers

    While both convert data, transform maps handle data transformation from import set tables to target tables, whereas robust import set transformers process data from source tables to message listeners. When both exist for a data source, the robust import set transformer takes precedence.

    Import Set Scheduled Cleanup

    To manage data volume, the Import Set Deleter scheduled job runs daily to remove import sets older than 7 days and their associated records. This cleanup prevents large import set tables from impacting system performance. If cleanup is not enabled, manual deletion of import set records may be necessary, especially when total records exceed 5 million.

    Manual Import Set Table Deletion

    Administrators can manually delete import set tables and related transform maps or clear only the data while preserving table structures. This helps maintain system hygiene and performance.

    Learn about import sets before importing data to your instance.

    The import sets table acts as a staging area for records imported from a data source.

    Note:
    Do not import data in extremely large chunks. Creating an extremely large import set can cause delays and system outages.

    A transform map determines the relationships between fields displaying in an import set table and fields in an existing ServiceNow table, such as the Incidents or Users table.

    Importing sets skip records when the data in the instance matches the data being imported.

    Note:
    Import sets run as user System and therefore cannot add data to encrypted fields.

    Import sets terminology

    Table 1. Key terms
    Term Definition
    Import Set table

    A table that acts as a staging location for records imported from a data source before transforming those records. Fields on these tables are generated automatically based on imported data and should not be modified manually.

    Note:
    Columns in an import set table are generated automatically and shouldn't be added manually. Manually adding columns can negatively impact the table's scheduled cleanup and may lead to an incomplete cleanup and orphaned records.

    If you need to add columns to an import set table, first add the column to the input data, then select Test Load 20 Records or Load All Records to auto generate the columns in the import set table.

    Columns in an import set table might not have the same type as the input data. For example, a currency column may be represented as a string column in an import set table until it's assigned to a target table column that is of type currency.

    Data source A record that defines where to get the data to import. A data source may point to a file, a JDBC-compatible database, or an LDAP organizational unit.
    Transformation The conversion of data from an import set table to another table according to the rules defined in a transform map.
    Transform map A set of field maps that define the relationships between fields in an import set and fields on a table, such as Incident.

    During transformation, data is copied from the Import Set table to the destination table based on the transform map.

    A single import set field may be mapped to multiple fields on other tables.

    Robust import set transformer Extract, transform, and load data to one or more target tables. Separate the transform and processing functions, providing a more flexible alternative to transform maps.
    Foreign record insert A foreign record insert occurs when an import makes a change to a table that is not the target table for that import.

    This change happens when updating a reference field on a table. For example, when updating a value for the caller on an incident, the import is actually updating the sys_user table.

    Coalesce Lets you update existing target table records when transforming import data.

    You can specify whether a Target field should be used to coalesce on when import set records are transformed. If the field map Coalesce option is selected, when the import set row is transformed, the instance checks for an existing record in the target table that has the same value in the Target field as the import set row Source field.

    If an existing record with a matching value in the target table is found, that record is updated. If no matching record is found, then a new record is created in the target table.

    Supported import formats

    You can import data from several different file formats or external data sources.

    Table 2. File formats
    Format Limitations
    CSV CSV files must comply with the proposed CSV standard in RFC4180. In particular, this means that double quotes may not appear inside fields. The first row of data in an imported CSV file becomes the header row and defines the columns for that import set.
    Excel Excel files must have the XLS or XLSX extension.
    XML XML files must have a consistent XPath for each data row.
    JSON
    • For JSON arrays, the path for each row must specify the array root element twice, such as /incidents/incidents.
    • JSON files should follow RFC-4627. For example, a single comma should separate a value from the following name. Names within an object should be unique.
    • Predicates such as @element, [index], or text(), as well as Axis such as children, siblings, or ancestors are not supported.
    Custom (Parse by Script) You can write custom JavaScript to parse input lines into the list of maps.

    The ServiceNow® platform can import data from the following external data sources.

    Table 3. External data sources
    Data Source Limitations
    JDBC JDBC imports require a valid transform map. Some network configurations may require a ServiceNow® MID Server.
    LDAP LDAP imports require a valid transform map.
    OIDC OIDC imports require a valid transform map.
    ServiceNow® REST (Integration Hub) REST imports require a valid transform map.
    Custom (Load by Script) Custom imports require a valid transform map.

    For more details about the different data sources, see Data sources.

    Transform maps versus robust import set transformers

    Both transform maps and robust import set transformers convert data. Transform maps convert data from the staging table to the destination file. Robust import set transformers convert data from a source table to a message listener. If a data source has both a transform map and a robust import set transformer, the system uses the robust import set transformer instead of the transform map.

    Import set scheduled cleanup

    The Import Set Deleter scheduled job cleans up old import set data every day at midnight.

    By default, the job deletes all import sets that are older than 7 days, as well as the associated import set table records. If this scheduled job is not active on your instance, activate it to mitigate the growing import set tables you may have, especially when using recurring imports.
    Note:
    If scheduled cleanup is not currently active on your system, you must ensure that your import set tables are not too large (> 5 million records total across all tables) before enabling this cleanup. If the tables are too large, manually delete the records first before proceeding. Contact Customer Service and Support to coordinate the deletion of this data.
    Figure 1. Scheduled Script Execution
    Import Set Deleter.

    For procedures, see Delete import sets.

    Import set table deleter

    You can manually delete any or all of the following import set tables:
    • Computer
    • User
    • Notification
    • Location
    You can also delete the related transform maps, or you can delete data only and preserve the table structure.
    Figure 2. Tables available for deletion
    Import set table deleter.

    For procedures, see Delete import set tables.