![]() ![]() A foreign key is a column, or a combination of columns, that refer to the primary key of another table. In the Foreign Keys tab, you can declare one or more foreign keys for the table. Select the columns to be part of the primary key by clicking the checkboxes in the Include field in the columns list.Optionally enter a constraint name for the primary key constraint in the Constraint Name field,.A primary key is a column, or a combination of columns, that uniquely identifies a row in a table. The Primary Key tab contains information about an optional primary key for the table. ![]() If you don't enter a required attribute or enter an attribute that is unsupported for a data type, you will get an error message when you click Execute to create the table. For instance, there is no metadata available to tell if a data type requires, or allows, a size. The Create Table dialog uses database metadata to try to enable only the fields that apply to the selected data type, but please note that it is not always possible. The Auto Increment field, and possibly Start With and Increment By fields, are shown for numeric fields if the database supports automatically inserting the next available sequence number in a numeric column. In the last two fields, specify if the table is nullable and a default value to use for rows inserted into the table without specifying a value for the column.īelow the column list, you may find additional fields depending on the features supported by the database you create the table for and the data type for the current column. The Collation field is shown for character columns if the database supports the declaration of a collation for textual data. ![]() For others, like the decimal types, you can may specify both a size and a scale (the maximal number of decimals),
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |