What is a ResultSetMetaData?

What is a ResultSetMetaData?

ResultSetMetaData is an interface in java. sql package of JDBC API which is used to get the metadata about a ResultSet object. Whenever you query the database using SELECT statement, the result will be stored in a ResultSet object. You can get this ResultSetMetaData object using getMetaData() method of ResultSet.

What is metadata in Java with example?

Metadata in Java defined as the data about the data is called “Metadata”. Metadata is also said to be documentation about the information which is required by the users. Real Time Examples: A library catalog, the table of content, data item about person data (person weight, a person walking, etc.), etc.

What is the use of ResultSetMetaData in Java?

The ResultSetMetaData provides information about the obtained ResultSet object like, the number of columns, names of the columns, datatypes of the columns, name of the table etc… Following are some methods of ResultSetMetaData class. Retrieves the number of columns in the current ResultSet object.

What is the different between ResultSet and ResultSetMetaData?

A ResultSet always maintains connection with the database. A RowSet can be connected, disconnected from the database. It cannot be serialized. A RowSet object can be serialized.

Do we need to close ResultSetMetaData?

You should explicitly close Statements , ResultSets , and Connections when you no longer need them, unless you declare them in a try -with-resources statement (available in JDK 7 and after). Connections to Derby are resources external to an application, and the garbage collector will not close them automatically.

What is metadata with example?

Metadata is data about data. A simple example of metadata for a document might include a collection of information like the author, file size, the date the document was created, and keywords to describe the document. Metadata for a music file might include the artist’s name, the album, and the year it was released.

What is the main purpose of ResultSetMetaData interface?

If you have to get metadata of a table like total number of column, column name, column type etc. , ResultSetMetaData interface is useful because it provides methods to get metadata from the ResultSet object.

How do I close a dataSource connection?

And this line wastefully opens a new connection only to immediately close it: dataSource. getConnection(). close();

Does commit close connection?

The transaction is committed when closing the connection with an open transaction (as @Mr. Shiny and New 安宇 stated.

How is the resultsetmetadata interface useful in Java?

Java ResultSetMetaData Interface. The metadata means data about data i.e. we can get further information from the data. If you have to get metadata of a table like total number of column, column name, column type etc. , ResultSetMetaData interface is useful because it provides methods to get metadata from the ResultSet object.

How to calculate number of columns in resultsetmetadata?

The following code fragment creates the ResultSet object rs, creates the ResultSetMetaData object rsmd, and uses rsmd to find out how many columns rs has and whether the first column in rs can be used in a WHERE clause. The constant indicating that a column does not allow NULL values.

How to get the resultsetmetadata object in JDBC?

Get the ResultSetMetaData object: Retrieve the ResultSetMetsdata object of the current ResultSet by invoking the getMetaData () method. Following JDBC program establishes connection with MySQL database, retrieves and displays the integer representing the data type of the 4th column in the MyPlayers table using the getColumnType () method.

What does the constant mean in resultsetmetadata Java?

The constant indicating that the nullability of a column’s values is unknown. Gets the designated column’s table’s catalog name. Returns the fully-qualified name of the Java class whose instances are manufactured if the method ResultSet.getObject is called to retrieve a value from the column.