Import wizard is a web based tool to process bulk records. With import wizard we can process maximum of 50,000 records. In import wizard we can’t see few objects (ex: if there is master detail relationship between two objects then child object we can’t see).
Data Loader is a client application for the bulk import or export of data. Use it to insert, update, delete, or export Salesforce records.
When importing data, Data Loader reads, extracts, and loads data from comma-separated values (CSV) files or from a database connection.
When exporting data, it outputs CSV files.
.CSV (Comma Separated Values)
In Dataloader settings we should enable ‘insert null values’ checkbox otherwise we can’t insert null values.
This is a field that usually references an ID from another (external) system.
if the customer has an Oracle Financials system that they will be linking with Salesforce, it may be easier for them to be able to refer to the Oracle ID of account records from within Salesforce. So they would create an external ID in Salesforce and they would load the Oracle ID into that field for each account. They can then refer to that ID field, rather than the Salesforce id.
The maximum value is 10,000 if the Use Bulk API option is selected. In a single insert, update, upsert, or delete operation, records moving to or from Salesforce are processed in increments of this size. The maximum is 200 records.
Enabling the Bulk API in Data Loader allows you to load or delete a large number of records faster than using the default SOAP-based API.
However, there are some differences in behavior in Data Loader when you enable the Bulk API. One important difference is that it allows you to execute a hard delete if you have the permission and license.