Set up the join table

Select Fields of the Current Data set can be added by setting the associated fields to facilitate the construction of SQL queries and SQL conditions.

  • External Table: The Dataset associated with the current (source) Dataset Properties table. Click the cell drop-down menu to select the Dataset in the Current Workspace as the Relation.
  • Field: a field in the source Dataset Properties table, which is associated with the external table.
  • Related Field: a field in the external table, which is associated with the Source Dataset. Select a field with the same properties as in Field.
  • Expression: Displays the join condition for joining this table and the external table. After the user sets the external table, Field, etc., the Application will automatically generate the join condition.
  • Join Type: supports left join and inner join.
    • Left Join: The number of valid records after joining is the same as that of the Source Dataset. The available field values are all the field values in the Source Dataset and all the matching field values in the Relation.
    • Inner join: The number of valid records after the join is the number of records that exactly match in the Source Dataset and Relation. The available field values are the field values that exactly match in the Source Dataset and Relation.
      Field Field 2
      1 1A
      2 2B
      3 3C
      4 4D
      Related Field Field 3
      1 10
      2 20
      3 30
      5 50
      Associated field Field 2 Field 3
      1 1A 10
      2 2B 20
      3 3C 30
      4 4D
      Associated field Field 2 Field 3
      1 1A 10
      2 2B 20
      3 3C 30
      Source Dataset Properties table Relation property sheet Left Link Search Result Inline Search Result
  • Join Rules: When multiple join conditions are added to the same external table, you can double-click the cell of the previous record Join Rules and set its relationship with the next join condition in the Drop-down Button. Two kinds of Join Rules, AND and OR, are provided, and the detailed description is as follows:
    • AND: Set Join Rules to AND if multiple join conditions need to be satisfied simultaneously.
    • OR: Set Join Rules to OR if only one of the join conditions needs to be satisfied.

Caution:
  • It is recommended that the associated field (Field, Related Field) be an integer, and that the field with index be used as the associated field.
    • After the external join table is added to the Dataset
  • in PostGIS Datasource, the program will automatically add quotation marks to the table name when performing SQL Query, Display Filter, and other expression construction operations. To resolve the database internal table name Case Sensitive.