Content Knowledge Summary
1: Establish a MySql database, and establish a related connection to the IDEA code.
2: Familiar with master conditions and sequential query.
Supplementary content screenshots
1: Find countries with a population greater than 8,016,521
Two: Query the total population of the Middle East
3: Query the countries with the longest and shortest life expectancy in the world
3: Textbook code analysis
11.1 The object sees only one row at a time, initially before the first row, and the next() method moves to the next sequential query operation. The return value of its method is 1 or 0 depending on whether the move is successful or not.
11.2: Get the number of records by moving the cursor to the last row to get its row number. The method is to encapsulate the code in the GetDatabaseConnection class.
11.3: Condition and sort query of where clause. (This example is sorted by date of birth).
11.4: For database updates, additions and deletions.
11.5: Use wildcards? in place of the field value.
11.6: The function of general query through the name of the data table column.
11.7: Handling correct transactions and dealing with failed transactions.