set configmap sql file

Question

I'm trying to make kubernetes deployment like this

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: data-claim
  labels:
    app: data-db
    tier: database
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 100Mi

---

apiVersion: v1
kind: ConfigMap
metadata:
  name: data-initdb-config
data:
  init.sql:
    


---

apiVersion: apps/v1
kind: Deployment
metadata:
  name: data-db
  labels:
    app: data-db
    tier: database
spec:
  selector:
    matchLabels:
      app: data-db
      tier: database
  strategy:
    type: Recreate
  template:
    metadata:
      labels:
        app: data-db
        tier: database
    spec:
      containers:
        - image: postgres:15.5
          name: database
          env:
            - name: POSTGRES_DB
              value: data
            - name: POSTGRES_USER
              value: user
            - name: POSTGRES_PASSWORD
              value: user
          ports:
            - containerPort: 5432
              name: data-db
          volumeMounts:
            - name: data-db-persistent-storage
              mountPath: /var/lib/postgresql/data
            - name: data-db-initdb
              mountPath: /docker-entrypoint-initdb.d
      volumes:
        - name: data-db-persistent-storage
          persistentVolumeClaim:
            claimName: data-claim
        - name: data-db-initdb
          configMap:
            name: data-initdb-config


---

apiVersion: v1
kind: Service
metadata:
  name: data-db-service
  labels:
    app: data-db
    tier: database
spec:
  ports:
    - port: 5432
      targetPort: 5432
  selector:
    app: data-db
    tier: database

I know that if I type initial sql at init.sql, it runs and shows on the deployment db.

But the problem is that sql is so long. I tried to deploy it but it cannot handle so that long (the sql line is about 2000s.) so I need to get sql file or get other way.

And I need to make .sh start for create extension. How should I make configmap with long .sql and .sh?