The VISIT_DIMENSION table represents sessions where observations were made. Each row represents one session (also called a visit, event or encounter). This session can involve a patient directly, such as a visit to a doctor's office, or it can involve the patient indirectly, as in when several tests are run on a tube of the patient's blood. More than one observation can be made during a visit. All visits must have a start date / time associated with them, but they may or may not have an end date. The visit record also contains specifics about the location of the session, such as the hospital or clinic the session occurred and whether the patient was an inpatient or an outpatient at the time of the visit.
Starting from version 1.6, this table will support custom columns apart from the required ones. The custom column in the table follows the same setup rule as the ones in the PATIENT_DIMENSION table. Please refer to the PATIENT_DIMENSION section for the data type mapping information.
The VISIT_DIMENSION table may have an unlimited number of optional columns but their data types and coding systems are specific to the local implementation. The default visit table is shown below.
VISIT_DIMENSION | ||
PK | ENCOUNTER_NUM | int |
PATIENT_NUM | int | |
ACTIVE_STATUS_CD | varchar(50) | |
START_DATE | datetime | |
END_DATE | datetime | |
INOUT_CD | varchar(50) | |
LOCATION_CD | varchar(50) | |
VISIT_BLOB | text | |
UPDATE_DATE | datetime | |
DOWNLOAD_DATE | datetime | |
IMPORT_DATE | datetime | |
SOURCESYSTEM_CD | varchar(50) | |
UPLOAD_ID | int |
The VISIT_DIMENSION table has one required column and two that should be present if at all possible :
REQUIRED: ENCOUNTER_NUM
- It is the primary key for the table; therefore it cannot contain duplicates.
- Cannot be null.
- Holds a reference number for the patient within the data repository.
- Integer field.
IMPORTANT: START_DATE
- Can be null.
- Contains the date the event began.
- Date-time field.
IMPORTANT: END_DATE
- Can be null.
- Contains the date the event ended.
- Date-time field.
Info
- A visit is considered to be an event; there is a distinct beginning and ending date and time for the event. However, these dates may not be recorded.
The rules for using the codes in the columns to perform queries are represented in the metadata and the values within the columns follow a similar pattern as previously described for the PATIENT_DIMENSION table.
- and the ACTIVE_STATUS_CD is used to record whether the event is still going on.
ACTIVE_STATUS_CD is intended to record whether an event is still going on. The schema below is not presently implemented, but it could be used within an ontology.
- Contains a code that represents the status of an event along with the precision of the available dates.
- Conceptually it is very similar to the VITAL_STATUS_CD column in the PATIENT_DIMENSION table.
- The code consists of two characters; the first one represents the validity of the END_DATE and the second one is for the START_DATE.
- These values are:
KEY:
"*" means that a second character should be the start date indicator (if exists)
"_" means that a first character should be the end date indicator (if exists)
Date Explained | Value | Description | |
End date | U* | Unknown | corresponds to a null END_DATE |
End date | O* | Ongoing | corresponds to a null END_DATE |
End date | (null)* | Known | END_DATE accurate to day |
End date | Y* | Known | END_DATE accurate to day |
End date | M* | Known | END_DATE accurate to month |
End date | X* | Known | END_DATE accurate to year |
End date | R* | Known | END_DATE accurate to hour |
End date | T* | Known | END_DATE accurate to minute |
End date | S* | Known | END_DATE accurate to second |
Start date | _L | Unknown | corresponds to a null START_DATE |
Start date | _A | Active | corresponds to a null START_DATE |
Start date | _(null) | Ongoing | START_DATE accurate to day |
Start date | _D | Ongoing | START_DATE accurate to day |
Start date | _B | Known | START_DATE accurate to month |
Start date | _F | Known | START_DATE accurate to year |
Start date | _H | Known | START_DATE accurate to hour |
Start date | _I | Known | START_DATE accurate to minute |
Start date | _C | Known | START_DATE accurate to second |
- The codes for this field were determined arbitrarily as there was no standardized coding system for their representation.
