# Table

This schema defines the Table entity. A Table organizes data in rows and columns and is defined by a Schema. OpenMetadata does not have a separate abstraction for Schema. Both Table and Schema are captured in this entity.

**$id:**[**https://open-metadata.org/schema/entity/data/table.json**](https://open-metadata.org/schema/entity/data/table.json)

Type: `object`

This schema <u>does not</u> accept additional properties.

## Properties
- **id** `required`
  - Unique identifier of this table instance.
  - $ref: [../../type/basic.json#/definitions/uuid](../types/basic.md#uuid)
- **name** `required`
  - Name of a table. Expected to be unique within a database.
  - $ref: [#/definitions/tableName](#tablename)
- **displayName**
  - Display Name that identifies this table. It could be title or label from the source services.
  - Type: `string`
- **fullyQualifiedName**
  - Fully qualified name of a table in the form `serviceName.databaseName.tableName`.
  - Type: `string`
- **description**
  - Description of a table.
  - Type: `string`
- **version**
  - Metadata version of the entity.
  - $ref: [../../type/entityHistory.json#/definitions/entityVersion](../types/entityhistory.md#entityversion)
- **updatedAt**
  - Last update time corresponding to the new version of the entity.
  - $ref: [../../type/basic.json#/definitions/dateTime](../types/basic.md#datetime)
- **updatedBy**
  - User who made the update.
  - Type: `string`
- **href**
  - Link to this table resource.
  - $ref: [../../type/basic.json#/definitions/href](../types/basic.md#href)
- **tableType**
  - $ref: [#/definitions/tableType](#tabletype)
- **columns** `required`
  - Columns in this table.
  - Type: `array`
    - **Items**
    - $ref: [#/definitions/column](#column)
- **tableConstraints**
  - Table constraints.
  - Type: `array`
    - **Items**
    - $ref: [#/definitions/tableConstraint](#tableconstraint)
- **owner**
  - Owner of this table.
  - $ref: [../../type/entityReference.json](../types/entityreference.md)
- **database**
  - Reference to Database that contains this table.
  - $ref: [../../type/entityReference.json](../types/entityreference.md)
- **location**
  - Reference to the Location that contains this table.
  - $ref: [../../type/entityReference.json](../types/entityreference.md)
- **viewDefinition**
  - View Definition in SQL. Applies to TableType.View only.
  - $ref: [../../type/basic.json#/definitions/sqlQuery](../types/basic.md#sqlquery)
- **tags**
  - Tags for this table.
  - Type: `array`
    - **Items**
    - $ref: [../../type/tagLabel.json](../types/taglabel.md)
- **usageSummary**
  - Latest usage information for this table.
  - $ref: [../../type/usageDetails.json](../types/usagedetails.md)
- **followers**
  - Followers of this table.
  - $ref: [../../type/entityReference.json#/definitions/entityReferenceList](../types/entityreference.md#entityreferencelist)
- **joins**
  - Details of other tables this table is frequently joined with.
  - $ref: [#/definitions/tableJoins](#tablejoins)
- **sampleData**
  - Sample data for a table.
  - $ref: [#/definitions/tableData](#tabledata)
- **tableProfile**
  - Data profile for a table.
  - Type: `array`
    - **Items**
    - $ref: [#/definitions/tableProfile](#tableprofile)
- **tableQueries**
  - List of queries that ran against a table.
  - Type: `array`
    - **Items**
    - $ref: [#/definitions/sqlQuery](#sqlquery)
- **changeDescription**
  - Change that lead to this version of the entity.
  - $ref: [../../type/entityHistory.json#/definitions/changeDescription](../types/entityhistory.md#changedescription)


## Type definitions in this schema

### tableType

- This schema defines the type used for describing different types of tables.
- Type: `string`
- The value is restricted to the following: 
  1. _"Regular"_
  2. _"External"_
  3. _"View"_
  4. _"SecureView"_
  5. _"MaterializedView"_

### dataType

- This enum defines the type of data stored in a column.
- Type: `string`
- The value is restricted to the following: 
  1. _"NUMBER"_
  2. _"TINYINT"_
  3. _"SMALLINT"_
  4. _"INT"_
  5. _"BIGINT"_
  6. _"BYTEINT"_
  7. _"FLOAT"_
  8. _"DOUBLE"_
  9. _"DECIMAL"_
  10. _"NUMERIC"_
  11. _"TIMESTAMP"_
  12. _"TIME"_
  13. _"DATE"_
  14. _"DATETIME"_
  15. _"INTERVAL"_
  16. _"STRING"_
  17. _"MEDIUMTEXT"_
  18. _"TEXT"_
  19. _"CHAR"_
  20. _"VARCHAR"_
  21. _"BOOLEAN"_
  22. _"BINARY"_
  23. _"VARBINARY"_
  24. _"ARRAY"_
  25. _"BLOB"_
  26. _"LONGBLOB"_
  27. _"MEDIUMBLOB"_
  28. _"MAP"_
  29. _"STRUCT"_
  30. _"UNION"_
  31. _"SET"_
  32. _"GEOGRAPHY"_
  33. _"ENUM"_
  34. _"JSON"_

### constraint

- This enum defines the type for column constraint.
- Type: `string`
- The value is restricted to the following: 
  1. _"NULL"_
  2. _"NOT_NULL"_
  3. _"UNIQUE"_
  4. _"PRIMARY_KEY"_

### tableConstraint

- This enum defines the type for table constraint.
- Type: `object`
- **Properties**
  - **constraintType**
    - Type: `string`
    - The value is restricted to the following: 
      1. _"UNIQUE"_
      2. _"PRIMARY_KEY"_
      3. _"FOREIGN_KEY"_
  - **columns**
    - List of column names corresponding to the constraint.
    - Type: `array`
      - **Items**
      - Type: `string`

### columnName

- Local name (not fully qualified name) of the column. ColumnName is `-` when the column is not named in struct dataType. For example, BigQuery supports struct with unnamed fields.
- Type: `string`
- The value must match this pattern: `^[^.]*$`
- Length: between 1 and 64

### tableName

- Local name (not fully qualified name) of a table.
- Type: `string`
- The value must match this pattern: `^[^.]*$`
- Length: between 1 and 64

### fullyQualifiedColumnName

- Fully qualified name of the column that includes `serviceName.databaseName.tableName.columnName[.nestedColumnName]`. When columnName is null for dataType struct fields, `field_#` where `#` is field index is used. For map dataType, for key the field name `key` is used and for the value field `value` is used.
- Type: `string`
- Length: between 1 and 256

### column

- This schema defines the type for a column in a table.
- Type: `object`
- This schema <u>does not</u> accept additional properties.
- **Properties**
  - **name** `required`
    - $ref: [#/definitions/columnName](#columnname)
  - **dataType** `required`
    - Data type of the column (int, date etc.).
    - $ref: [#/definitions/dataType](#datatype)
  - **arrayDataType**
    - Data type used array in dataType. For example, `array<int>` has dataType as `array` and arrayDataType as `int`.
    - $ref: [#/definitions/dataType](#datatype)
  - **dataLength**
    - Length of `char`, `varchar`, `binary`, `varbinary` `dataTypes`, else null. For example, `varchar(20)` has dataType as `varchar` and dataLength as `20`.
    - Type: `integer`
  - **dataTypeDisplay**
    - Display name used for dataType. This is useful for complex types, such as `array<int>, map<int,string>, struct<>, and union types.
    - Type: `string`
  - **description**
    - Description of the column.
    - Type: `string`
  - **fullyQualifiedName**
    - $ref: [#/definitions/fullyQualifiedColumnName](#fullyqualifiedcolumnname)
  - **tags**
    - Tags associated with the column.
    - Type: `array`
      - **Items**
      - $ref: [../../type/tagLabel.json](../types/taglabel.md)
  - **constraint**
    - Column level constraint.
    - $ref: [#/definitions/constraint](#constraint)
  - **ordinalPosition**
    - Ordinal position of the column.
    - Type: `integer`
  - **jsonSchema**
    - Json schema only if the dataType is JSON else null.
    - Type: `string`
  - **children**
    - Child columns if dataType or arrayDataType is `map`, `struct`, or `union` else `null`.
    - Type: `array`
      - **Items**
      - $ref: [#/definitions/column](#column)

### columnJoins

- This schema defines the type to capture how frequently a column is joined with columns in the other tables.
- Type: `object`
- This schema <u>does not</u> accept additional properties.
- **Properties**
  - **columnName**
    - $ref: [#/definitions/columnName](#columnname)
  - **joinedWith**
    - Fully qualified names of the columns that this column is joined with.
    - Type: `array`
      - **Items**
        - Type: `object`
      - **Properties**
        - **fullyQualifiedName**
          - $ref: [#/definitions/fullyQualifiedColumnName](#fullyqualifiedcolumnname)
        - **joinCount**
          - Type: `integer`

### tableJoins

- This schema defines the type to capture information about how columns in this table are joined with columns in the other tables.
- Type: `object`
- This schema <u>does not</u> accept additional properties.
- **Properties**
  - **startDate**
    - Date can be only from today going back to last 29 days.
    - $ref: [../../type/basic.json#/definitions/date](../types/basic.md#date)
  - **dayCount**
    - Type: `integer`
    - Default: `1`
  - **columnJoins**
    - Type: `array`
      - **Items**
      - $ref: [#/definitions/columnJoins](#columnjoins)

### tableData

- This schema defines the type to capture rows of sample data for a table.
- Type: `object`
- This schema <u>does not</u> accept additional properties.
- **Properties**
  - **columns**
    - List of local column names (not fully qualified column names) of the table.
    - Type: `array`
      - **Items**
      - $ref: [#/definitions/columnName](#columnname)
    - **rows**
      - Data for multiple rows of the table.
      - Type: `array`
        - **Items**
          - Data for a single row of the table within the same order as columns fields.
          - Type: `array`

### columnProfile

- This schema defines the type to capture the table's column profile.
- Type: `object`
- This schema <u>does not</u> accept additional properties.
- **Properties**
  - **name**
    - Column Name.
    - Type: `string`
  - **uniqueCount**
    - No. of unique values in the column.
    - Type: `number`
  - **uniqueProportion**
    - Proportion of number of unique values in a column.
    - Type: `number`
  - **nullCount**
    - No.of null values in a column.
    - Type: `number`
  - **nullProportion**
    - No.of null value proportion in columns.
    - Type: `number`
  - **min**
    - Minimum value in a column.
    - Type: `string`
  - **max**
    - Maximum value in a column.
    - Type: `string`
  - **mean**
    - Avg value in a column.
    - Type: `string`
  - **median**
    - Median value in a column.
    - Type: `string`
  - **stddev**
    - Standard deviation of a column.
    - Type: `number`

### tableProfile

- This schema defines the type to capture the table's data profile.
- Type: `object`
- This schema <u>does not</u> accept additional properties.
- **Properties**
  - **profileDate**
    - Data one which profile is taken.
    - $ref: [../../type/basic.json#/definitions/date](../types/basic.md#date)
  - **columnCount**
    - No.of columns in the table.
    - Type: `number`
  - **rowCount**
    - No.of rows in the table.
    - Type: `number`
  - **columnProfile**
    - List of local column profiles of the table.
    - Type: `array`
      - **Items**
      - $ref: [#/definitions/columnProfile](#columnprofile)

### sqlQuery

- This schema defines the type to capture the table's sql queries.
- Type: `object`
- **Properties**
  - **query**
    - SQL Query text that matches the table name.
    - Type: `string`
  - **duration**
    - How long did the query took to run in seconds.
    - Type: `number`
  - **user**
    - User who ran this query.
    - $ref: [../../type/entityReference.json](../types/entityreference.md)
  - **vote**
    - Users can vote up to rank the popular queries.
    - Type: `number`
    - Default: `1`
  - **checksum**
    - Checksum to avoid registering duplicate queries.
    - Type: `string`
  - **queryDate**
    - Date on which the query ran.
    - $ref: [../../type/basic.json#/definitions/date](../types/basic.md#date)

_This document was updated on: Monday, November 15, 2021_