I am relatively new to using Postgres, coming from a MySQL background. I am
using Postgres 9.3.4 on Windows x64.
We are being supplied data in multiple fixed length text files. The first
digit on each line is a number between 1 and 4 that indicates the record
type of the data in that row. The rows are grouped sequentially such that
there will always first be a row of type 1 followed by zero or more rows of
the other types.
data_x.txt --------------------- 1data01 2data02 4data03 4data04 1data05 1data06 3data07
To import this into Postgres I have used the following SQL commands:
CREATE TABLE data_raw ( raw_data TEXT ); COPY data_raw FROM 'C:\path\data_x.txt' ...; -- Repeated for
eachfile ALTER TABLE data_raw ADD COLUMN indicator integer; UPDATE data_raw SET indicator =
CAST(substr(raw_data,1, 1) AS integer), raw_data = substr(raw_data, 2);
I then create tables for each of the 4 record types:
CREATE TABLE table_1 SELECT raw_data FROM data_raw WHERE indicator = 1; CREATE TABLE table_2 SELECT raw_data FROM
data_rawWHERE indicator = 2; CREATE TABLE table_3 SELECT raw_data FROM data_raw WHERE indicator = 3; CREATE TABLE
table_4SELECT raw_data FROM data_raw WHERE indicator = 4;
What I need to do, but am unsure how, is to also add an "id" column for each
group where the indicator starts with 1. We will be getting weekly updates
so I need to specify the initial id for each batch. So if this batch starts
at id = 225, then I want to get the following tables from the sample data:
table_1 id | raw_data -------------------- 225 | data01 226 | data05 227 | data06 table_2 id |
raw_data -------------------- 225 | data02 table_3 id | raw_data -------------------- 227 | data07
table_4 id | raw_data -------------------- 225 | data03 225 | data04
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