Table Editor
The Table Editor application provides a graphical method of creating, inspecting, and modifying table structures in Informix databases. When the utility is first entered, the user chooses a server, then a database on that server, and finally a table within that database. This choice of server/database/table can also be made directly from the toolbar or from the menu using the Table→Open menu choice or the Open Folder toolbar button.
The Table Editor has three main tabbed pages, Columns, Indexes, and Foreign Keys. Much of the useful information is in the Columns tab. From the Table→Properties menu, the user sees a screen listing several items of interest regarding the table. The Status tab shows name, owner, modification date, row size, and number of rows, columns, and indexes. Under the General tab is information about extent sizing and locking levels. The Constraints tab shows any constraints defined in the table. Finally, the Location tab shows information about how the table is physically laid out. It allows the user to place the table in a default database, in its own dbspace, or partitioned across multiple dbspaces.
Under the Columns tab, the user can name or rename columns or attributes. Clicking on any of the column type entries produces a drop-down box that gives the user a choice of all Informix data types.
Using either the toolbar or the Columns menu option from the menu, the user can insert or delete columns as well as declare a column part of the primary key and define its properties. These properties include the column name, data type, size or precision, default values, and whether or not the column can be null. Clicking on the size/precision or allow nulls cell in the Columns tab will open listboxes allowing the user use the mouse to select the desired information.
The Indexes tab shows index name and columns as graphical icons that also indicate whether or not the value is indexed as ascending or descending. When on the index tabbed page, the user can create a new index using the menu choice Indexes→ New Index. This calls the Index Wizard, which walks the user through creating a new index. This wizard allows the user to specify:
Index name
Columns used
Order of the columns in the index
Whether the columns are sorted ascending or descending
Whether the index is unique
Whether the index is clustered
Whether the index is stored with the table, in its own dbspace, or across multiple dbspaces
Clicking on the Foreign Key tab, the user sees any defined foreign key constraints in the database. By using the menu or the toolbar, the user can use the Foreign Key Wizard to define these relationships This wizard allows the user to:
Name the foreign key
Select a table to relate to the current table
Choose a primary key or constraint for the foreign key constraint
Define the join between the two tables for the foreign key
Choose whether or not to use cascading deletes on the foreign key table
Both of these wizards greatly simplify the creation and modifications of indexes and foreign keys. While most DBAs are proficient with creating indexes using the character-based tools, they often miss some of the fine points such as location of the indexes. Foreign keys may or may not be used often. If used infrequently, the DBA usually has to dig into the documentation for the correct syntax. These two wizards can make either of these functions much easier and much less error prone.
As in all of the other GUI tools, the Table Editor provides cut and paste capability with other Windows applications.