Java – JDBC 4 – Update Annotation Example

The Update annotation is used to decorate a Query interface method to update one or more records in a database table. An Update annotation must include a sql annotation type element. Here’s an example of Update annotation:

interface LoanAppDetailsQuery extends BaseQuery {
    @Update(sql="update LoanDetails set LoanStatus = ?1 where loanId = ?2")
    boolean updateLoanStatus(String loanStatus, int loanId);
}

Java – JDBC 4 – Select Annotation Example

Here’s an example of Select annotation to get all the active loans from the loan database:

interface LoanAppDetailsQuery extends BaseQuery {
    @Select("SELECT * FROM LoanDetais where LoanStatus = 'A'")
    DataSet<LoanApplication> getAllActiveLoans();
}

The sql annotation allows I/O parameters as well (a parameter marker is represented with a question mark followed by an integer). Here’s an example of a parameterized sql query.

interface LoanAppDetailsQuery extends BaseQuery {
    @Select(sql="SELECT * from LoanDetails where borrowerFirstName= ?1 and borrowerLastName= ?2")
    DataSet<LoanApplication> getLoanDetailsByBorrowerName(String borrFirstName, String borrLastName);
}

Java JDBC – Connect to PostgreSQL Database

Download PostgreSQL JDBC Driver:
http://jdbc.postgresql.org/download.html

Code Snippet:

Class.forName("org.postgresql.Driver");
Connection connection = null;
connection = DriverManager.getConnection(
   "jdbc:postgresql://hostname:port/dbname","username", "password");
connection.close();

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