Example usage for java.sql ResultSetMetaData columnNullableUnknown

Introduction

In this page you can find the example usage for java.sql ResultSetMetaData columnNullableUnknown.

Prototype

int columnNullableUnknown

To view the source code for java.sql ResultSetMetaData columnNullableUnknown.

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Document

The constant indicating that the nullability of a column's values is unknown.

Usage

From source file:Main.java

public static void main(String[] args) throws Exception {
    Class.forName(DRIVER);/*from w  ww  .  j  a v  a 2 s .c om*/
    Connection connection = DriverManager.getConnection(URL, USERNAME, PASSWORD);

    Statement statement = connection.createStatement();
    ResultSet resultSet = statement.executeQuery("SELECT id, username FROM users");
    ResultSetMetaData metadata = resultSet.getMetaData();
    int nullability = metadata.isNullable(1);

    if (nullability == ResultSetMetaData.columnNullable) {
        System.out.println("Columns ID can have a null value");
    } else if (nullability == ResultSetMetaData.columnNoNulls) {
        System.out.println("Columns ID does not allowed to have a null value");
    } else if (nullability == ResultSetMetaData.columnNullableUnknown) {
        System.out.println("Nullability unknown");
    }
}

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From source file:com.alibaba.wasp.jdbc.TestPreparedStatement.java

public void testParameterMetaData() throws SQLException {
    PreparedStatement prep = conn.prepareStatement("SELECT ?, ?, ? FROM DUAL");
    ParameterMetaData pm = prep.getParameterMetaData();
    assertEquals("java.lang.String", pm.getParameterClassName(1));
    assertEquals("VARCHAR", pm.getParameterTypeName(1));
    assertEquals(3, pm.getParameterCount());
    assertEquals(ParameterMetaData.parameterModeIn, pm.getParameterMode(1));
    assertEquals(Types.VARCHAR, pm.getParameterType(1));
    assertEquals(0, pm.getPrecision(1));
    assertEquals(0, pm.getScale(1));//from w ww.j a  v a2s  . c om
    assertEquals(ResultSetMetaData.columnNullableUnknown, pm.isNullable(1));
    assertEquals(pm.isSigned(1), true);
    assertThrows(SQLErrorCode.INVALID_VALUE_2, pm).getPrecision(0);
    assertThrows(SQLErrorCode.INVALID_VALUE_2, pm).getPrecision(4);
    prep.close();
    assertThrows(SQLErrorCode.OBJECT_CLOSED, pm).getPrecision(1);

    Statement stat = conn.createStatement();
    stat.execute("CREATE TABLE TEST3(ID INT, NAME VARCHAR(255), DATA DECIMAL(10,2))");
    PreparedStatement prep1 = conn.prepareStatement("UPDATE TEST3 SET ID=?, NAME=?, DATA=?");
    PreparedStatement prep2 = conn.prepareStatement("INSERT INTO TEST3 VALUES(?, ?, ?)");
    checkParameter(prep1, 1, "java.lang.Integer", 4, "INTEGER", 10, 0);
    checkParameter(prep1, 2, "java.lang.String", 12, "VARCHAR", 255, 0);
    checkParameter(prep1, 3, "java.math.BigDecimal", 3, "DECIMAL", 10, 2);
    checkParameter(prep2, 1, "java.lang.Integer", 4, "INTEGER", 10, 0);
    checkParameter(prep2, 2, "java.lang.String", 12, "VARCHAR", 255, 0);
    checkParameter(prep2, 3, "java.math.BigDecimal", 3, "DECIMAL", 10, 2);
    PreparedStatement prep3 = conn
            .prepareStatement("SELECT * FROM TEST3 WHERE ID=? AND NAME LIKE ? AND ?>DATA");
    checkParameter(prep3, 1, "java.lang.Integer", 4, "INTEGER", 10, 0);
    checkParameter(prep3, 2, "java.lang.String", 12, "VARCHAR", 0, 0);
    checkParameter(prep3, 3, "java.math.BigDecimal", 3, "DECIMAL", 10, 2);
    stat.execute("DROP TABLE TEST3");
}

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