How to design Database

A relational database cannot store multiple values in a single field. You will have to create a separate record/table and relate them.

Before starting to build that in Appian, I suggest to look for some training material in the internet.

When asked your question, ChatGPT told me this:

Certainly! To store data in an array format in a database, you have a few options depending on the type of database you are using. Below are some common approaches for different types of databases:

### 1. **Relational Databases (e.g., MySQL, PostgreSQL)**

In relational databases, you typically don't store arrays directly. Instead, you can use one of the following methods:

- **JSON Data Type**: Many modern relational databases support a JSON data type, which allows you to store arrays as JSON.

**Example (PostgreSQL)**:
```sql
CREATE TABLE your_table (
id SERIAL PRIMARY KEY,
data JSONB
);

INSERT INTO your_table (data) VALUES ('[1, 2, 3, 4]');
```

**Example (MySQL)**:
```sql
CREATE TABLE your_table (
id INT AUTO_INCREMENT PRIMARY KEY,
data JSON
);

INSERT INTO your_table (data) VALUES ('[1, 2, 3, 4]');
```

- **Separate Table**: Create a separate table to store the array elements, with a foreign key relationship to the main table.

**Example**:
```sql
CREATE TABLE your_table (
id SERIAL PRIMARY KEY
);

CREATE TABLE your_array_table (
id SERIAL PRIMARY KEY,
your_table_id INT,
value INT,
FOREIGN KEY (your_table_id) REFERENCES your_table(id)
);
```

### 2. **NoSQL Databases (e.g., MongoDB)**

NoSQL databases like MongoDB are designed to handle unstructured data, including arrays, natively.

**Example**:
```javascript
db.your_collection.insertOne({
data: [1, 2, 3, 4]
});
```

### 3. **Using an Array Data Type (PostgreSQL)**

If you are using PostgreSQL, you can also use the built-in array data type.

**Example**:
```sql
CREATE TABLE your_table (
id SERIAL PRIMARY KEY,
data INT[]
);

INSERT INTO your_table (data) VALUES (ARRAY[1, 2, 3, 4]);
```

### 4. **Using a Text Field (as a last resort)**

If your database does not support JSON or array types, you can store the array as a delimited string (e.g., comma-separated values) in a text field. However, this approach is less efficient and more complex to query.

**Example**:
```sql
CREATE TABLE your_table (
id SERIAL PRIMARY KEY,
data TEXT
);

INSERT INTO your_table (data) VALUES ('1,2,3,4');
```

### Conclusion

Choose the method that best fits your use case and the capabilities of your database. If you are using a relational database, the JSON data type or a separate table is often the best approach. If you are using a NoSQL database, you can store arrays directly.

Stefan Helzle said:

cannot store multiple values in a single field

I mean, it can (as your chatGPT answer noted), but to your point, the conditions are far more limited / limiting than properly creating individual rows.  if we know up-front that the "multiple values" will be fairly limited and fairly consistent, my favorite method is to use a JSON string (with the DB just handling the string part, and Appian handling the JSON part).  I don't know if Appian is all that compatible with DB table columns of "json type", whatever that might imply (unless it's just renamed plaintext of some sort).

Stefan Helzle said:

cannot store multiple values in a single field

I mean, it can (as your chatGPT answer noted), but to your point, the conditions are far more limited / limiting than properly creating individual rows.  if we know up-front that the "multiple values" will be fairly limited and fairly consistent, my favorite method is to use a JSON string (with the DB just handling the string part, and Appian handling the JSON part).  I don't know if Appian is all that compatible with DB table columns of "json type", whatever that might imply (unless it's just renamed plaintext of some sort).

I agree to everything you said.

BTW, Appian can use JSON data fields in DB, just not all the JSON specific DB functions. For Appian, it is just text. In the DB, using stored procedures, you can do much more, and treat the JSON just like any other structure,

That's cool - so out of curiosity, does declaring the column type as JSON add any particular value?  I've done the MariaDB-side JSON conversions before on simple plaintext (in stored procedures as well as views and/or just basic DB maintenance utilities), but not sure if the column typing somehow makes it easier.

Should I declare it as text for status message field then?

I will get this data via integration and i want it to be in an array. 

Integration output :

{
ID:1,
CaseID: 12,
email :Test,
addid:1193u,
remove id:123,
status:success,
statausmessage:
{
     {
          message :test1 success, 
          date:
       }
         {
             message : test2 failed,
             date:
          }
    
  }

If it were me, I'd declare the column as text, and wrap the "statusmessage" array in JSON before writing.  Be cautious, though, that the number of Status Messages doesn't potentially get problematically large, i.e. enough to break the column if the width grows too large.  If it could grow to hundreds of messages (or potential messages with very long text), then it might be time to consider an association table instead.

Associated table in this sense new table with fields message and date and foreign key to the table

yes - since then you'd be able to store any number of associated messages (with their date) tied to any given parent entry, without worrying about space, and somewhat more easy searching/querying/filtering as well.  the up-front difficulty would be a little higher but it buys you more flexibility later.  it's definitely a trade-off so you will need to consider carefully which approach to take.

In my case 

{
ID:1,
CaseID: 12, ----Foreign Key from Main table .
email :Test,
addid:1193u,

removeid:134,

.........................}

In this table  I already have an foreign key  as CaseID and I need to get for each email address the status.

So I want to modify the existing table by adding  status as message .

Can you please suggest

basically you would need to choose your approach, between adding a brand new table to store the status messages, with a simple foreign key to whatever table the individual messages woudl inherently belong to, as well as the timestamp and the message text - or, instead, add a text column in that table where you can store the message array in JSON (assuming the array never grows all that large, and you won't need to do much querying on it).