Update a Data Row Using the UpdaTable ResultSet – Insert, Update and Delete Data from Databases

7.5.2.2  Update a Data Row Using the UpdaTable ResultSet
Copy the project OracleUpdaTableInsert, change its name to OracleUpdaTableUpdate and save it to your default folder, Class DB Projects\Chapter 7.

Then open this new project, double-click on the Update button from the FacultyFrame Form window to open its event handler and modify the code shown in Figure 7.21 to perform the data update function using the UpdaTable ResultSet object.
Let’s have a closer look at this piece of modified code to see how it works.

A. First, we add an if block to distinguish the Java executeQuery Method and the Java UpdaTable ResultSet method to perform this data update action.

B. An else if block is added with the same objective as step A.

C. The query string is created, and it is used to help the UpdaTable ResultSet object do this data update action.

D. A try-catch block is used to perform this data update action. A PreparedStatement is created with two ResultSet parameters, TYPE _ SCROLL _ SENSITIVE and CONCUR _ UPDATable, to define the ResultSet object to enable it to be scrollable and updaTable and to perform data manipulations.

E. The setString() method is used to initialize the positional parameter in the query string.

F. The executeQuery() method is called to perform this query and return the query result to a new created ResultSet object.
G. First we need to identify the location of the row to be updated. There is only one row that has been retrieved from our Faculty Table and saved in the ResultSet, which may be any default faculty member, and this row will be updated in this data update action. Therefore, the absolute position for this row is 1. Then a sequence of updateString() methods is executed to update the desired columns to the associated columns in the ResultSet. The point to be noted is that different updateXXX() methods should be used if the target columns have the different data types, and the XXX indicates the associated data type, such as Int, Floator Double.

H. For the image column, the system method updateBytes() must be used to update a faculty image in the Faculty Table.

FIGURE 7.21   The modified code for the Update button click event handler.