java.sql: public interface: Blob

java.sql
public interface: Blob [javadoc | source]

All Known Implementing Classes:
SerialBlob

The representation (mapping) in the Java^TM programming language of an SQL BLOB value. An SQL BLOB is a built-in type that stores a Binary Large Object as a column value in a row of a database table. By default drivers implement Blob using an SQL locator(BLOB), which means that a Blob object contains a logical pointer to the SQL BLOB data rather than the data itself. A Blob object is valid for the duration of the transaction in which is was created.

Methods in the interfaces ResultSet , CallableStatement , and PreparedStatement , such as getBlob and setBlob allow a programmer to access an SQL BLOB value. The Blob interface provides methods for getting the length of an SQL BLOB (Binary Large Object) value, for materializing a BLOB value on the client, and for determining the position of a pattern of bytes within a BLOB value. In addition, this interface has methods for updating a BLOB value.

All methods on the Blob interface must be fully implemented if the JDBC driver supports the data type.

since: 1.2 -

Method from java.sql.Blob Summary:
free, getBinaryStream, getBinaryStream, getBytes, length, position, position, setBinaryStream, setBytes, setBytes, truncate

Method from java.sql.Blob Detail:
public void free() throws SQLException This method frees the `Blob` object and releases the resources that it holds. The object is invalid once the `free` method is called. After `free` has been called, any attempt to invoke a method other than `free` will result in a `SQLException` being thrown. If `free` is called multiple times, the subsequent calls to `free` are treated as a no-op.
public InputStream getBinaryStream() throws SQLException Retrieves the `BLOB` value designated by this `Blob` instance as a stream.
public InputStream getBinaryStream(long pos, long length) throws SQLException Returns an `InputStream` object that contains a partial `Blob` value, starting with the byte specified by pos, which is length bytes in length.
public byte[] getBytes(long pos, int length) throws SQLException Retrieves all or part of the `BLOB` value that this `Blob` object represents, as an array of bytes. This `byte` array contains up to `length` consecutive bytes starting at position `pos`.
public long length() throws SQLException Returns the number of bytes in the `BLOB` value designated by this `Blob` object.
public long position(byte[] pattern, long start) throws SQLException Retrieves the byte position at which the specified byte array `pattern` begins within the `BLOB` value that this `Blob` object represents. The search for `pattern` begins at position `start`.
public long position(Blob pattern, long start) throws SQLException Retrieves the byte position in the `BLOB` value designated by this `Blob` object at which `pattern` begins. The search begins at position `start`.
public OutputStream setBinaryStream(long pos) throws SQLException Retrieves a stream that can be used to write to the `BLOB` value that this `Blob` object represents. The stream begins at position `pos`. The bytes written to the stream will overwrite the existing bytes in the `Blob` object starting at the position `pos`. If the end of the `Blob` value is reached while writing to the stream, then the length of the `Blob` value will be increased to accomodate the extra bytes. Note: If the value specified for `pos` is greater then the length+1 of the `BLOB` value then the behavior is undefined. Some JDBC drivers may throw a `SQLException` while other drivers may support this operation.
public int setBytes(long pos, byte[] bytes) throws SQLException Writes the given array of bytes to the `BLOB` value that this `Blob` object represents, starting at position `pos`, and returns the number of bytes written. The array of bytes will overwrite the existing bytes in the `Blob` object starting at the position `pos`. If the end of the `Blob` value is reached while writing the array of bytes, then the length of the `Blob` value will be increased to accomodate the extra bytes. Note: If the value specified for `pos` is greater then the length+1 of the `BLOB` value then the behavior is undefined. Some JDBC drivers may throw a `SQLException` while other drivers may support this operation.
public int setBytes(long pos, byte[] bytes, int offset, int len) throws SQLException Writes all or part of the given `byte` array to the `BLOB` value that this `Blob` object represents and returns the number of bytes written. Writing starts at position `pos` in the `BLOB` value; `len` bytes from the given byte array are written. The array of bytes will overwrite the existing bytes in the `Blob` object starting at the position `pos`. If the end of the `Blob` value is reached while writing the array of bytes, then the length of the `Blob` value will be increased to accomodate the extra bytes. Note: If the value specified for `pos` is greater then the length+1 of the `BLOB` value then the behavior is undefined. Some JDBC drivers may throw a `SQLException` while other drivers may support this operation.
public void truncate(long len) throws SQLException Truncates the `BLOB` value that this `Blob` object represents to be `len` bytes in length. Note: If the value specified for `pos` is greater then the length+1 of the `BLOB` value then the behavior is undefined. Some JDBC drivers may throw a `SQLException` while other drivers may support this operation.