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Query around Primary Key in Appian My SQL Database

komalc3
A Score Level 1

Hi All,

 

I am working on version 18.1.

 

I have a few queries around Primary Key in Appian's MY SQL database:

 

1. In my MySQL database, if I want to create two columns as primary key i.e. if I want to create a composite key rather than making just one column as a primary key then how can I do that as in my data type Appian allows to create only one column as primary key though in XSD we can add two columns as primary key using @Id annotation. So I would like to know how can I achieve this or I can only create one column as primary key.

2. Also would like to know in which scenario do I get Unique Key Constraint violated error.

 

Thanks in advance!!

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  • 0
    A Score Level 1
    Hi komalc,

    The constraints occur in the following cases:
    Databases can enforce constraints on column values that are not enforced by Appian on CDT field values.

    For example, a database may require a column value to be "not null", but the field in Appian can be empty. Be aware of these differences when designing your data stores.

    Use the attribute nillable="true" to prevent columns in your data store from enforcing a "non-null" constraint.


    You can create additional column to save combination values of (Value 1) and (value 2) Make that additional column as PK in your CDT.
    From DB side Additional Column should be Unique Key, PK is (value 1 and value 2)

    For more info , please have a look on docs.appian.com/.../Database_Schema_Best_Practices.html

    Thanks,
    ravalik
Reply
  • 0
    A Score Level 1
    Hi komalc,

    The constraints occur in the following cases:
    Databases can enforce constraints on column values that are not enforced by Appian on CDT field values.

    For example, a database may require a column value to be "not null", but the field in Appian can be empty. Be aware of these differences when designing your data stores.

    Use the attribute nillable="true" to prevent columns in your data store from enforcing a "non-null" constraint.


    You can create additional column to save combination values of (Value 1) and (value 2) Make that additional column as PK in your CDT.
    From DB side Additional Column should be Unique Key, PK is (value 1 and value 2)

    For more info , please have a look on docs.appian.com/.../Database_Schema_Best_Practices.html

    Thanks,
    ravalik
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