# DocumentPageImageById ## Documentation One page of a document as a JPEG image. Fetched once per machine and then answered from the shared disk cache. One request per call; a removed or unknown id answers no rows. - Catalog: `OpenBesluitvorming` - Schema: `Files` - Primary Keys: `entity_id, page_number, scale` This is a read-only table function. The Open Besluitvorming API may not support changing the data or the Invantive UniversalSQL driver for Open Besluitvorming does not cover it. In the latter case, please use the table NativePlatformScalarRequests to upload data to the Open Besluitvorming API. ## Parameters of Table Function The following parameters can be used to control the behaviour of the table function `DocumentPageImageById`. A value must be provided at all times for required parameters, but optional parameters in general do not need to have a value and the execution will default to a pre-defined behaviour. Values can be specified by position and by name. In both cases, all parameters not specified will be evaluated using their default values. Value specification by position is done by listing all values from the first to the last needed value. For example: a `select * from table(value1, value2, value3)` on a table with four parameters will use the default value for the fourth parameter and the specified values for the first three. Value specification by name is done by listing all values that require a value. For example with `select * from table(name1 => value1, name3 => value3)` on the same table will use the default values for the second and fourth parameters and the specified values for the first and third. | Name | Data Type | Required | Default Value | Documentation | |---|:---:|:---:|:---:|---| | `entity_id` | `varchar2` | ☑ | | The document. | | `page_number` | `number` | ☑ | | The page, from 1. | | `scale` | `number` | ☐ | | 1 for 96 dpi (the default), 2 for 192 dpi. | ## Columns of Table Function The columns of the table function `DocumentPageImageById` are shown below. Each column has an SQL data type. | Name | Data Type | Label | Required | Documentation | |---|:---:|---|:---:|---| | `content_type` | `varchar2` | | ☐ | image/jpeg. | | `contents` | `blob` | | ☐ | The image. | | `entity_id` | `varchar2` | | ☑ | The document. | | `page_count` | `int32` | | ☐ | The number of pages of the document. | | `page_number` | `int32` | | ☑ | The page. | | `scale` | `int32` | | ☑ | 1 or 2. |