docs : adding primary value

Signed-off-by: Naveen MR <oof1lab@gmail.com>

packages/noco-docs/content/en/setup-and-usages/570_formulas.md

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 title: "Formulas"
 description: "Formulas"
-position: 580
+position: 570
 category: "Usage"
 menuTitle: "Formulas"
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packages/noco-docs/content/en/setup-and-usages/575_primary-value.md

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+---
+title: "Primary value"
+description: "Primary value"
+position: 575
+category: "Usage"
+menuTitle: "Primary value"
+---
+
+## What is a 'Primary value' ?
+- Primary value as the name stands is the primary or main value within a row of a table that you generally associate that row with.
+- It should be usually associated with a column which is uniquely identifiable. However, this uniqueness is not enforced at the database level.
+
+
+## What is the use of 'Primary value' ?
+- Within a spreadsheet, primary value are always highlighted so that it is easier to recognise what row we are in.
+- And when LinkToAnotherRecord is created between two tables - it is the primary value that appears in LinkToAnotheRecord column. 
+
+## How is ```Primary value``` identfied for existing database tables ?
+- It is usually the first column after the primary key which is not a number. 
+- If there is no column which is not a number then the column adjacent to primary key is chosen. 
+
+## Can I change the ```Primary Value``` to another column within tables ?
+- Yes, you can. Hover over column which you want as primary column and click ```Set as Primary Value```