dup_field - Linux
Overview
dup_field copies specified fields from source_table
to target_table
while preserving data integrity and performance. It automatically handles data type conversion, field addition, and update operations.
Syntax
dup_field source_table target_table [field1 field2 ...]
Options/Flags
- -y: Overwrite existing target fields without confirmation.
- -v: Enable verbose output, providing detailed progress information.
- –dry-run: Preview the changes without making any modifications to the tables.
Examples
Example 1: Copy specific fields
Copy the name
and age
fields from source_table
to target_table
:
dup_field source_table target_table name age
Example 2: Copy all fields (except a few)
Copy all fields except id
and created_at
from source_table
to target_table
:
dup_field source_table target_table --exclude id created_at
Example 3: Dry run
Preview the changes without modifying the tables:
dup_field source_table target_table name age --dry-run
Common Issues
- Ensure that both
source_table
andtarget_table
exist and have the correct permissions. - Check that the specified fields exist in
source_table
and are compatible with the data types intarget_table
. - Avoid using
dup_field
on very large tables, as it can be resource-intensive. Consider using a batch processing tool for such scenarios.
Integration
Example 1: Post-insertion data migration
Automatically copy new records from source_table
to target_table
after insertion:
pg_triggers --create --trigger update_target_table --table source_table --whenever insert --execute 'dup_field source_table target_table name age'
Example 2: Data synchronization
Synchronize data between table1
and table2
on a regular basis using a cron job:
0 0 * * * dup_field table1 table2 --overwrite