The Edit Column dialog allows you to edit the properties of table columns before the table is created. This dialog is accessible from the Create Table Wizard, Import Table Wizard, and Import Database Wizard.
The main area of the dialog 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);
- Include into Index - check this option to allow the column to included into a primary, unique, full-text, or usual index.
- Primary Key - specify this option to include the field into the table primary key;
- Unique Key - check this option to create a unique index for the field;
- Full-Text Key - this option is available for CHAR, VARCHAR, or TEXT fields; it allows you to perform relevance-based search within the field;
- Key Sub-Part - this option specifies the part of the CHAR or VARCHAR field, which will be used for searching;
- Comment - an arbitrary description for the column.
The properties pane allows you to define the advanced properties of the column. 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.
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