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TENANT
{ "_ID" : 11, NAME : "ruben", OPERATION :[{OPERATION_ID: 100, NAME : "Check"}] }
how to set the OPERATION_ID has unique to avoid duplicate values and to avoid null values like primary key?
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To get distinct values, use distinct() in MongoDB. It finds the distinct values for a specified field across a single collection or view and returns the results in an array.
You can select a single field in MongoDB using the following syntax: db. yourCollectionName. find({"yourFieldName":yourValue},{"yourSingleFieldName":1,_id:0});
Right-click the table on which you want to create a unique index and select Design. On the Table Designer menu, select Indexes/Keys. In the Indexes/Keys dialog box, click Add. Select the new index in the Selected Primary/Unique Key or Index text box.
Unique indexes are indexes that help maintain data integrity by ensuring that no rows of data in a table have identical key values. When you create a unique index for an existing table with data, values in the columns or expressions that comprise the index key are checked for uniqueness.
When you want the OPERATION_IDs to be unique for all tenants, then you can do it like that:
db.tenants.ensureIndex( { operation.OPERATION_ID : 1 }, { unique:true, sparse:true } );
When you want the OPERATION_IDs to be unique per tenant, so that two tenants can both have the operation_ID:100 but no tenant can have operation_id:100 twice, you have to add the _id of the tenant to the index so that any given combination of _id and operation_id is unique.
db.tenants.ensureIndex( { _id: 1, operation.OPERATION_ID : 1 }, { unique:true, sparse:true } );
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