`<column>`

The <column> element defines a single-value field in the entity.

Note: For a discussion of <column-override>, see Working with attribute and element overrides for details.

Attributes of `<column>`

The <column> element contains the following attributes:

`<column>` attribute	Description	Default
`allowInitialValueForUpgrade`	Internal use.	`false`
`autoincrement`	The name of a database sequence used as the source of values for the column. This attribute is applicable only for integer columns, and only for implementations where PolicyCenter relies on the database for the sequence. Do not use the same sequence in more than one `autoincrement` column. There can be at most one `autoincrement` column per table.	None
`columnName`	Optional. If specified, PolicyCenter uses this value as the column name of the corresponding database column. If you do not specify a `columnName` value, then PolicyCenter uses the value of the `name` attribute for the database column name. The columnName attribute must be no more than 30 characters in length. It allows only unaccented Roman letters, numbers, and the underscore character. The first character of the columnName attribute must be a letter. Although the underscore character is allowable here, Guidewire discourages its use. IMPORTANT All column names on a table must be unique within that table. Otherwise, Guidewire Studio™ displays an error if you verify the resource and the application server fails to start.	None
`createhistogram`	Whether to create a histogram on the column during an update to the database statistics. Note: It is possible to override this attribute on an existing column in an extension (.etx) file using the `<column-override>` element. You can use the override to turn off an existing histogram or to create one that did not previously exist. This change does not take effect during an upgrade. The change occurs only if you regenerate statistics for the affected table by using the Guidewire maintenance_tools command. See also* Working with attribute and element overrides Understanding database statistics maintenance_tools command	`false`
`default`	Default value given to the field during new entity creation. Note: For columns with the datetime data type, see Date value syntax for the syntax to use for the value of the default attribute.	None
`deprecated`	If `true`, then PolicyCenter marks the item as deprecated in the Data Dictionary and places a `Deprecated` annotation on it in the Guidewire Studio API Reference. If you deprecate an item, use the description to explain why. For more information, see Data entity subelements.	`false`
`desc`	A description of the purpose and use of the field.	None
`exportable`	Unused.
`getterScriptability`	See Data objects and scriptability for information.	`all`
`ignoreforevents`	If you change, add, or remove an entity X that does not generate events, then PolicyCenter searches for all event-generating entity instances that specify X. If PolicyCenter finds any of these event-generating entity instances, it generates `Changed` events for those entity instances. To determine what entities reference a non-event-generating entity, PolicyCenter examines the foreign keys and arrays that point to the entity. However, if you set `ignoreForEvents` to `true` on an entity that references the non-event-generating entity, then PolicyCenter ignores that link as it determines what entities specify another entity. At the entity level, the `ignoreForEvents` attribute means changes to (or addition or removal of) this entity do not cause `Changed` events to fire for any other entity. At the column level, the `ignoreForEvents` attribute means changes to this column do not cause the application to generate events.	`false`
`loadable`	If `true`, you can load the field through staging tables. A staging table can contain a column mapping to the field.	`true`
`loadedByCallback`	Internal. If true, then the loading code does not use a default value or report a warning if the column is nullable without a default.	`false`
`name`	Required. The name of the column on the table and the field, or property, on the entity. PolicyCenter uses this value as the column name unless you specify a `columnName` attribute. Use this name to access the column in data views, rules, and other areas within PolicyCenter. IMPORTANT All column names on a table must be unique within that table. Otherwise, Studio displays an error if you verify the resource and the application server fails to start.	None
`nullok`	Whether the column can contain `null` values. In general, this attribute is always `true`, as many tables include columns that do not require a value at different points in the process.	`true`
`overwrittenInStagingTable`	Internal. If `true` and the entity is loadable, the loader process auto-populates the staging table during import. IMPORTANT If set to `true`, do not attempt to populate the table yourself as the loader import process overwrites this table.	`false`
`required`	Whether the column is required to be non-null upon initial construction of instances of the entity. See Special behaviors for entity types during instantiation.	`false`
`scalable`	Whether this value scales as the effective and expired dates change. This attribute applies only to number-type values. For example, you cannot scale a `varchar`. Also, it only applies to effective dated types.	`false`
`setterScriptability`	See Data objects and scriptability for information.	`all`
`soapnullok`	Unused.
`supportsLinguisticSearch`	Applies only to columns of `varchar`-based data types. If `true`, case insensitive searches can be performed on the denormalized version of the column. If `false`, searches are binary and cannot be performed on a denormalized version of the column. You cannot use this attribute with an encrypted column. The setting of this attribute does not affect locale or language used in searches. See also Configuring search in the PolicyCenter database Including data from subentities	`false`
`type`	Required. Data type of the column, or field. In the base configuration, Guidewire defines a number of data types and stores their metadata definition files (.dti) in under configuration > config > datatypes. Each metadata definition file name is the name of a specific data type. You use one of these data types as the `type` attribute on the `<column>` element. Thus, the list of valid values for the `type` attribute is the same as the set of .dti files in the application datatypes folders. Each metadata definition also defines the value type for that data type. The value type determines how PolicyCenter treats that value in memory. The name of the data type is not necessarily the same as the name of its value type. For example, for the `bit` data type, the name of the data type is `bit` and the corresponding value type is `java.lang.Boolean`. Similarly, the data type `varchar` has a value type of `java.lang.String`. The `datetime` data type is a special case. PolicyCenter persists this data type in the application database using the database data type `TIMESTAMP`. This corresponds to the value type `java.util.Date`. In other words: PolicyCenter represents a column whose type is `datetime` in memory as instances of `java.util.Date`. PolicyCenter stores this type of value in the database as `TIMESTAMP`. Note:* Guidewire does not support the unlimiteddecimal data type in a persistent data model configuration. See also Data types Customizing base configuration data types Define a new data type	None

Subelements of `<column>`

The <column> element contains the following subelements:

`<column>` subelement	Description	Default
`columnParam`	See <columnParam> subelement.	None
`fulldescription`	See <fulldescription>.	None
`localization`	See <localization> subelement.	None
`tag`	See <tag>.	None