The Columns tab contains the list of table fields and the right pane, which allows you to tune the detailed properties for the table field, selected in the list. The buttons on the toolbar and the popup menu of the list allow you to insert new columns in various ways, delete columns, and change the column positions.
You can add a column to the list in one of the following ways:
- Insert Default - inserts a column with all properties set to default;
- Insert Domain - inserts a column with all properties set according to the selected domain (e.g. AutoNumber - INT, PK, NOT NULL, AUTOINC; Text - VARCHAR, LENGTH 25, etc.);
- Duplicate Column - inserts a column with all properties set identical to the selected column;
- Insert Lookup - allows you to select a parent table and column for the inserted column, and inserts the column along with a new relationship.
See the Domain Designer and the Insert Lookup Dialog for details.
The Move Up and Move Down buttons allow you to change the column positions. You can also use the Ctrl+Up and Ctrl+Down key combinations for the same purposes respectively.
The column list displays all the columns in the table and allows you to modify the following column properties:
- Column Name - the name of the column, which must be unique within the table;
- Data Type - the type of the column, which specifies data to store in the column; it can be one of integer types, which differ in data size (TINYINT, SMALLINT, MEDIUMINT, INT, BIGINT), decimal type (FLOAT, DOUBLE, DECIMAL), a type for storing date and time values (DATE, DATETIME, TIMESTAMP, TIME, YEAR), string type (CHAR, VARCHAR), a large binary type (TINYBLOB, BLOB, MEDUIMBLOB, LONGBLOB), a multi-line text (TINYTEXT, TEXT, MEDIUMTEXT, LONGTEXT), enumeration type, which can contain only values from the Set attribute (ENUM), or a set of values from the Set attribute (SET);
- Primary Key - specify this option to include the field into the table primary key;
- Comment - an arbitrary description for the column.
The properties pane allows you to define the advanced properties of the column, selected in the Column List. The appearance of this pane changes according to the data type of the column. These properties are:
- Length - this attribute defines the maximum allowed length of the stored values; it applies to all integer, decimal, and string types;
- Decimals - this attribute defines the number of digits, which follow the decimal point in the FLOAT, DOUBLE, and DECIMAL types;
- Not null - this option indicates that the stored column value cannot be NULL;
- Binary - this attribute indicates that the string value is stored in a binary form within the column;
- Unsigned - this option indicates that the stored integer or decimal value must be above zero;
- Zerofill - with this attribute all unspecified digits of the field value are filled as zeros according to the column Length and Decimals; it applies to all integer and decimal types;
- Unique - this option indicates that the column value must be unique within the table, creating a unique index for the column;
- Autoinc - this attribute makes the column value autoincrement, i.e. each new value is set automatically according to the previous value; it applies to all integer values;
- Set - this attribute defines the list of permissible values for the field of the ENUM or SET type;
- Default - this attribute defines the default value, which the column accepts if no other is specified.
You can customize the column list and the properties pane. Click the Customize button on the toolbar or in the popup menu to change the display properties of the Table Designer within the Customize Column Design dialog.
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