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for sequences, account for nulls and zero #112

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for sequences, account for nulls and zero #112

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648ae04
for sequences, account for nulls and zero
jhere1 Aug 22, 2023
35aa32c
set sequence nextval to 1 by setting isUsed to false
jhere1 Sep 7, 2023
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10 changes: 8 additions & 2 deletions src/SequencesProcessor.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -67,7 +67,10 @@ export const setSequenceValue = async (

const seqName: string = getSequenceName(tableName, columnName);
const sql = `SELECT SETVAL(\'"${conversion._schema}"."${seqName}"\',
(SELECT MAX("${columnName}") FROM "${conversion._schema}"."${tableName}"));`;
GREATEST(
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@jhere1
In general - good catch!
The question is, shouldn't we set sequence value to zero if table is empty?

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Yeah, the nextval would have been 2. Setting sequence value to 0 would involve changing the sequence definition min value. Take a look at my latest commit. Think this is cleaner. it does what we want (have nextval be 1) by saying the value of 1 is not used yet.

COALESCE((SELECT MAX("${columnName}") FROM "${conversion._schema}"."${tableName}"), 0)
, 1), false
);`;

const params: DBAccessQueryParams = {
conversion: conversion,
Expand Down Expand Up @@ -140,7 +143,10 @@ export const createIdentity = async (conversion: Conversion, tableName: string):
params.client = createSequenceResult.client;
params.shouldReturnClient = false;
params.sql = `SELECT SETVAL(\'"${conversion._schema}"."${seqName}"\',
(SELECT MAX("${columnName}") FROM ${fullTableName}));`;
GREATEST(
COALESCE((SELECT MAX("${columnName}") FROM ${fullTableName}), 0)
, 1), false
);`;

const sqlSetSequenceValueResult: DBAccessQueryResult = await DBAccess.query(params);

Expand Down