YSQL reserves the following names for internal usage. Exception will be raised when these names are used even when they are double-quoted.

| Names | Description |
|-------|-------------|
| `oid` | System column |
| `tableoid` | System column |
| `xmin` | System column |
| `cmin` | System column |
| `xmax` | System column |
| `cmax` | System column |
| `ctid` | System column |
| `ybctid` | Virtual column |
| Prefixed with `pg_` | System database objects |
| Prefixed with `yb_` | System database objects |