Fields: Table

On the Fields page determine the structure of the table being created, that is, specify the list of table fields and their properties:

To add a new field, click the Add button. A string is added to the end of the list, in which specify field properties:

Type/Data Type. Select data type in the drop-down list:

String. Default value.
Integer.
Real.
Date and time.

Name. Enter a name that describes field value. The default name: Field <Number>.
Identifier. Determine a unique table field name to be used for SQL queries and to determine links between tables. Identifier can have only Latin letters, numbers and underline character. The default identifier: FIELD<Number>.
Total Length. Determine the maximum length of table field: this value represents the number of characters for the character type or the number of digits for the numeric type.
Decimal Places. Determine the number of fractional decimal places for numeric fields.
Empty Values. Select the checkbox to determine whether a field can store empty values.

NOTE. If ClickHouse DBMS is selected on the Properties page, and the Empty Values checkbox is deselected, the default value is entered to the table field when an empty record is added. To change automatic entering of values, use the input_format_null_as_default parameter in ClickHouse DBMS settings.

Default Value. Determine the value that goes automatically into every new created table field. For example, one can enter the most frequently occurring value.
Value/Calculated Field. Use the drop-down list to determine whether a field is calculated. When a calculated field is set, a confirmation dialog box opens warning the user about deleting all field data. After the operation is confirmed, set a formula, which will calculate field value. To do this, click the Insert into Formula button. The expression editor window opens.

To change the number of displayed properties, select or deselect checkboxes next to property names in the drop-down menu of the Settings button.

Expression Editor

The expression editor window for setting up calculated fields of external table looks as follows:

Operands, arithmetic operations, functions, numbers, comparison characters and round brackets can be used in a formula. There are some features of use:

All element types, except for numbers, can be inserted both using the keyboard or special panels.
Numbers are inserted only using the keyboard.

Operands are displayed on the expression editor's operands panel:

Other table fields and parameters are used as operands.

To insert an operand to the formula area, execute one of the operations:

Using the operands panel:

Select the operand and click the Insert into Formula button.
Double-click the operand.
Drag the operand to the formula area.

Using the formula area:

Enter the operand name in the formula area.
Click in the formula area in the place where the operand should be inserted, press CTRL+SHIFT and select the required operand on the popup panel.

To quickly search for an operand, start typing partial or full name of the operand in the search string. After executing the operation the operands panel displays the operands, which names satisfy search conditions.

To set up displaying of the operands list, use items in the drop-down menu of the Display Settings button:

Name. Default value. Only operand names are displayed.
Identifier. Only operand identifiers are displayed.
Name and Identifier. Operand names and identifiers are displayed in the format: <name> (<identifier>).

To hide the operands panel, click the Hide Operands Panel button. To show the panel, click the Show Operands Panel button.

Insert functions and statements

Table Fields

Expression Editor