ETL+ Load Replace Examples_OLD

Examples of source data and the target tables that result from a Load Replace.

Example 1

Extract, Transform and Load (ETL) page

The seq column represents a sequentially incremented value.

Design page. No PK (primary key) in target table.

Source

csv file

Preview

Target Table Before

Empty

Target Table After

SSMS

Log: (4 rows loaded)

2nd Load Replace

row 4 (seq = 104) has
seq = Max(seq)

Log: (1 rows replaced)

3rd Load Replace

row 2 updated after last load, row 2 and 4 will be extracted

MAX(seq) = 4

1 = pre-existing row,
not changed
2 = new row
3 = replaced

Log: (2 rows replaced)

The Target Table has two rows with a row column = 2.
If the row column had been configured as a DW PK (primary key) on the Design page then the relational database referential integrity rule would have updated the existing row instead of adding a new row.