JDBC stands for Java Database Connectivity which resides in java.sql package and contains Connection, Statement, PreparedStatement, CallableStatement, and ResultSet.
Connection(I)
Used to establish connection with database.
PreparedStatement
Use to execute parameterized sql query.
Use this instead of Statement.
Difference between executeQuery and executeUpdate
executeQuery: used for retrieval queries.
executeUpdate: used for deletion, update, and insert queries.
PreparedStatement setter methods
setInt(int paramIndex, int value)
setString(int paramIndex, String value)
and many more based on datatype you need to set.
ResultSet
Maintains a cursor pointing to a row of a table. By default it points at 0 hence the indexing starts at 1.
ResultSet indexing methods
next: move to next row.
previous: move back from previous row.
first: move to first row of the result set.
last: move to last row of the result set.
ResultSet fetching methods
There are 2 ways to retrive a value from result set is by column name and column index.
getInt(int columnIndex)
getInt(String columnName)
getString(int columnIndex)
getString(String columnName)
and many more based on the return values of youre query.
Tips used try-with resources for much cleaner and readable code. and add log for debugging purposes.
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