espocrm-base/application/Espo/Resources/metadata/entityDefs/ArrayValue.json

{
    "fields": {
        "value": {
            "type": "varchar",
            "required": true,
            "maxLength": 100
        },
        "entity": {
            "type": "linkParent"
        },
        "attribute": {
            "type": "varchar",
            "maxLength": 100
        }
    },
    "indexes": {
        "entityTypeValue": {
            "columns": ["entityType", "value"]
        },
        "entityValue": {
            "columns": ["entityType", "entityId", "value"]
        }
    },
    "hooksDisabled": true
}