Fetch only True values of particular keys from table using python without pandas?

Question

I am trying to take values from a DB table where It has keys as enabled and values as true, false and empty, I want to take only True values from enabled keys and other keys and rows related to it.

Table

    id    name    enabled dept
     1    abd     TRUE    cs
     2    cdew    FALSE   ds
     3    sda             sd
     4    asd     TRUE    as

I want only enabled = true values from table. how can I do it? without help of pandas? I want like

    id    name    enabled dept
     1    abd     TRUE    cs
     4    asd     TRUE    as

Hi, @Mia ! Which database do you use? In case of SQL databases like MySQL or PostgreSQL it would be better to use SQL for filtering data, not Python. — Alex R
– Alex R, Commented Nov 7, 2022 at 11:43
Are you using the Python API? boto3.amazonaws.com/v1/documentation/api/latest/reference/… KeyConditionExpression=Key('enabled').eq(True) — Paul Bauriegel
– Paul Bauriegel, Commented Nov 7, 2022 at 12:00
no im using table scan with ProjectionExpression and ExpressionAttributeNames — Mia
– Mia, Commented Nov 7, 2022 at 12:12
Better create a GSI on the enabled column and use the query operation instead of scan. Scan operation is costly as your data will increase — Vikram S
– Vikram S, Commented Nov 7, 2022 at 12:29

Leeroy Hannigan · Accepted Answer · 2022-11-07 19:36:39Z

1

Best thing to do is create a Sparse Index which only had the True values.

To do this, only set enabled for True values and if False just omit it as DynamoDB is schemaless.

Now create a GSI with the partition or sort key as enabled, now the GSI will only contain the items you want. To fetch them simply Scan the GSI. GSI:

id(pk)  enabled(sk) name   dept
 1       TRUE       abd     cs
 4       TRUE       asd     as

edited Nov 7, 2022 at 19:36

answered Nov 7, 2022 at 19:20

Leeroy Hannigan

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2 Comments

Mia Over a year ago

pls send any docs related to the exact GSI

Leeroy Hannigan Over a year ago

docs.aws.amazon.com/amazondynamodb/latest/developerguide/…

Mia · Accepted Answer · 2022-11-08 08:25:25Z

0

I solved it using below code. thanks all for your help

resp= key.get('enabled',None)
if resp:

answered Nov 8, 2022 at 8:25

Mia

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