嗨!
我想从 sqlite 数据库中读取 blob 数据,但总是收到此错误消息
08.05.2012 15:06:28 org.hibernate.engine.jdbc.spi.SqlExceptionHelper logExceptions
WARN: SQL Error: 0, SQLState: null
08.05.2012 15:06:28 org.hibernate.engine.jdbc.spi.SqlExceptionHelper logExceptions
ERROR: not implemented by SQLite JDBC driver
我正在使用 JSF、Spring、JPA(休眠)。
Sqlite 表结构
CREATE TABLE LOGO ('logo_id' INTEGER PRIMARY KEY NOT NULL, 'logo_data' BLOB)
读取一行代码:
public void loadLogo() {
try {
Query query = entityManager.createNativeQuery("SELECT * FROM logo");
Vector v = (Vector) query.getSingleResult();
byte[] blobData = (byte[]) v.elementAt(1);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
Sqlite 方言:
public class SQLiteDialect extends Dialect implements Serializable {
private static final long serialVersionUID = 1L;
public SQLiteDialect() {
registerColumnType(Types.BIT, "integer");
registerColumnType(Types.TINYINT, "tinyint");
registerColumnType(Types.SMALLINT, "smallint");
registerColumnType(Types.INTEGER, "integer");
registerColumnType(Types.BIGINT, "bigint");
registerColumnType(Types.FLOAT, "float");
registerColumnType(Types.REAL, "real");
registerColumnType(Types.DOUBLE, "double");
registerColumnType(Types.NUMERIC, "numeric");
registerColumnType(Types.DECIMAL, "decimal");
registerColumnType(Types.CHAR, "char");
registerColumnType(Types.VARCHAR, "varchar");
registerColumnType(Types.LONGVARCHAR, "longvarchar");
registerColumnType(Types.DATE, "date");
registerColumnType(Types.TIME, "time");
registerColumnType(Types.TIMESTAMP, "timestamp");
registerColumnType(Types.BINARY, "blob");
registerColumnType(Types.VARBINARY, "blob");
registerColumnType(Types.LONGVARBINARY, "blob");
registerColumnType(Types.NULL, "null");
registerColumnType(Types.BLOB, "blob");
registerColumnType(Types.CLOB, "clob");
registerColumnType(Types.BOOLEAN, "integer");
registerFunction("concat", new VarArgsSQLFunction(
StandardBasicTypes.STRING, "", "||", ""));
registerFunction("mod", new SQLFunctionTemplate(
StandardBasicTypes.INTEGER, "?1 % ?2"));
registerFunction("substr", new StandardSQLFunction("substr",
StandardBasicTypes.STRING));
registerFunction("substring", new StandardSQLFunction("substr",
StandardBasicTypes.STRING));
}
public boolean supportsIdentityColumns() {
return true;
}
/*
* public boolean supportsInsertSelectIdentity() { return true; // As
* specify in NHibernate dialect }
*/
public boolean hasDataTypeInIdentityColumn() {
return false; // As specify in NHibernate dialect
}
/*
* public String appendIdentitySelectToInsert(String insertString) { return
* new StringBuffer(insertString.length()+30). // As specify in NHibernate
* dialect append(insertString).
* append("; ").append(getIdentitySelectString()). toString(); }
*/
public String getIdentityColumnString() {
// return "integer primary key autoincrement";
return "integer";
}
public String getIdentitySelectString() {
return "select last_insert_rowid()";
}
public boolean supportsLimit() {
return true;
}
protected String getLimitString(String query, boolean hasOffset) {
return new StringBuffer(query.length() + 20).append(query)
.append(hasOffset ? " limit ? offset ?" : " limit ?")
.toString();
}
public boolean supportsTemporaryTables() {
return true;
}
public String getCreateTemporaryTableString() {
return "create temporary table if not exists";
}
public boolean dropTemporaryTableAfterUse() {
return false;
}
public boolean supportsCurrentTimestampSelection() {
return true;
}
public boolean isCurrentTimestampSelectStringCallable() {
return false;
}
public String getCurrentTimestampSelectString() {
return "select current_timestamp";
}
public boolean supportsUnionAll() {
return true;
}
public boolean hasAlterTable() {
return false; // As specify in NHibernate dialect
}
public boolean dropConstraints() {
return false;
}
public String getAddColumnString() {
return "add column";
}
public String getForUpdateString() {
return "";
}
public boolean supportsOuterJoinForUpdate() {
return false;
}
public String getDropForeignKeyString() {
throw new UnsupportedOperationException(
"No drop foreign key syntax supported by SQLiteDialect");
}
public String getAddForeignKeyConstraintString(String constraintName,
String[] foreignKey, String referencedTable, String[] primaryKey,
boolean referencesPrimaryKey) {
throw new UnsupportedOperationException(
"No add foreign key syntax supported by SQLiteDialect");
}
public String getAddPrimaryKeyConstraintString(String constraintName) {
throw new UnsupportedOperationException(
"No add primary key syntax supported by SQLiteDialect");
}
public boolean supportsIfExistsBeforeTableName() {
return true;
}
public boolean supportsCascadeDelete() {
return false;
}
}
请帮我!
谢谢