# Loader

## Prerequisites for Database data

| Notes on uniqueness when exporting user data In logical import DataView assigns new ident numbers in the target system. The precondition for that is the uniqueness of the table data in the loader file. DataView assures this by automatically detecting key fields during export and marking them with a (*) symbol. Because the binary loader file is not editable, it is now important to assure uniqueness of table data before exporting. Please observe the following notes: Master tables Before exporting you must mark at least one field as unique, e.g. a number field. Relation tables n:m When relation records are exported, DataView uses the unique combination of C_ID_1 and C_ID_2 and automatically forms a key. If an additional unique field is defined (e.g. to allow multiple relations), DataView will form the key based on the settings in the uniqueness flag. You do not have to do anything before exporting. Relation tables 1:n to the zero entity Before exporting you must mark at least one field as unique, because C_ID_1 is always the same for a parent element, while C_ID_2 is always zero. Type tables When exporting type records in 1:1 type relations DataView automatically uses C_ID_2 to form a unique key. If an additional unique field is defined for 1:n type relations, DataView will form the key based on the settings in the uniqueness flag. You do not have to do anything before exporting.
| Selection criteria You can limit data export by specifying selection criteria. The binary loader offers essentially extended selection criteria. You can specify limitations not only regarding owner-user/group or date of creation/update, but also regarding any internal system fields or application-specific attribute fields. In the list you choose selection fields and enter the desired search terms for each field. Search terms for several fields are AND-combined and the conventions for search terms correspond to those of the -> standard function Query. Depending on the tables to be exported, the choice box at the field fieldname offers all fields available for defining selection criteria. This results in different opportunities to limit export to certain data: DataView system fields global (C_VERSION ... C_ACC_OGW) Globally (in all tables) limits expor of records to entries in the DataView system fields. For instance you can only export records with a certain version identifier (C_VERSION), a certain owner identifier (C_UIC), or a certain date of creation (C_CRE_DAT). DataView system fields for each individual table (TABLE NAME.C_VERSION ... TABLE NAME.C_ACC_OGW) Limits the export of records for certain individual tables to entries in DataView system fields. For instance, within one data stock you can export records from one table only after a certain date of creation (C_CRE_DAT), while all data from other tables are not affected by these limitations. Application-specific attribute fields (TABLE NAME.COLUMN NAME) Limits export of records by entries in certain application-specific attribute fields. For instance you can export only field objects with a certain name from the DataView system table T_FIELD. Joins for each individual table (TABLE NAME-<JOIN) Limits export of records by entries in other tables. It is a precondition, however, that the other table is related to the offered one and is contained in the list of tables to be exported. You must enter the name of the related table as a search term. For instance, when exporting field objects from T_FIELD you could make sure that only the table- and mask objects related to the fields are exported by using a join from T_MASK to T_MAS_FLD and from T_TABLE to T_TAB_FLD. Links for each individual table (TABLENAME-<CONS) Limits the export to the linked records of a depending table. It is a requirement, however, that both tables linked via DTV-Constraint are contained in the table list. If you then select DEPENDING TABLE-<CONS in the field Field Name and move on with TAB, DataView will automatically enter the name of the link into the query field.
| Attention! Tables containing a BLOB field can not be exported as dependent tables with the binary loader (link via "TABLE NAME<JOIN" or "TABLE NAME-<CONST"). Currently this behavior cannot be changed!
| Automatic pre-assignment of fields When exporting table fields you can automatically assign pre-defined values to table fields now. In the list you select fields and enter the required pre-assigned texts. Depending on the tables to be exported the choice box at the field fieldname offers the following fields: DataView system fields global (C_VERSION ... C_ACC_OGW) Global automatic pre-assignment of DataView system fields, i.e. for all tables. DataView system fields for each individual table (TABLE NAME.C_VERSION ... TABLE NAME.C_ACC_OGW) Automatic pre-assignment of DataView system fields for certain individual tables. Application-specific attribute fields (TABLE NAME.COLUMN NAME) Automatic pre-assignment for individual application-specific attribute fields.
| The pre-assignment of date fields must be done using the database date format YYYY-MM-DD HH:MM:SS.
| You can define an automatic pre-assignment of fields for export, depending on whether the loader files already contain the pre-assignment