How to check if a column exists in apache phoenix?

Question

我们如何使用Java确定Apache Phoenix中的表上是否已存在列？

Answer 1

Normal DB query would be this.

SELECT COUNT(*) FROM SYSTEM.CATALOG WHERE TABLE_NAME = 'TABLE_NAME' AND COLUMN_NAME = 'COL_NAME';

Checking via java (You could get this by running the above query and checking for count as well).

public static boolean doesColumnExists(String connectionStr, String tableName, String columnName)
        throws SQLException {
    Connection phoenixConnection = DriverManager.getConnection(connectionStr);
    DatabaseMetaData databaseMetaData = phoenixConnection.getMetaData();
    ResultSet colResult = databaseMetaData.getColumns("", "", tableName, columnName);
    return colResult.next();
}