Outputs change-only-update CSV files (or “delta” files) that contain all the necessary actions required to re-synchronize rows in a cloned table.
const generateDeltaFile = require('pg-delta-file')
const deltaInfo = await generateDeltaFiles(
since: '2017-07-16T20:37:26.847Z',
outputFilepath: '/some/temp/dir/people-delta.csv',
actionAliases: {
insert: 'u',
update: 'u',
delete: 'd'
},
createdColumnName: '_created',
modifiedColumnName: '_modified',
transformFunction: (row, callback) => { ... } // optional data transformation
filterFunction: (row) => { ... } // option filter predicate
dryrun: true // optional flag, set true to return info without generating output file
csvExtracts: {
'[schema.]people': [
'PERSON', // Just output a literal
'$ACTION', // Will output 'u' or 'd'
'$ROW_NUM', // Row counter
'@social_security_id', /// Column data
'@first_name',
'@last_name',
'@age'
'$DATESTAMP',
'$TIMESTAMP',
'$DATETIMESTAMP',
],
'[schema2.]address': [
...
]
}
)
/*
{
"totalCount": 5,
"people": {
"totalCount": 5
},
"address": {
"totalCount": 3
"filteredCount": 2
}
}
*/
$ npm install pg-delta-file --save