CVI_EI_LONGTEXT_DATA_KEY is a standard SAP Structure so does not store data like a database table does. It can be used to define the fields of other actual tables or to process "Ext. Interface: Key for Long Texts" Information within sap ABAP programs. This is done by declaring abap internal tables, work areas or database tables based on this Structure. These can then be used to store and process the required data appropriately. i.e. DATA: wa_CVI_EI_LONGTEXT_DATA_KEY TYPE CVI_EI_LONGTEXT_DATA_KEY.
The CVI_EI_LONGTEXT_DATA_KEY table consists of various fields, each holding specific information or linking keys about Ext. Interface: Key for Long Texts data available in SAP. These include LANGU (Language Key), LANGUISO (2-Character SAP Language Code)... See below for full list along with technical details, documentation, text table, check tables, foreign key relationships, conversion routines, relevant tcodes and example ABAP select code etc. .