【问题标题】:How to connect sqlite database to weka如何将sqlite数据库连接到weka
【发布时间】:2016-10-21 15:42:02
【问题描述】:

我正在尝试将数据库从 sqlite3 导入到 weka,但问题是即使在加载并显示数据库之后,当我单击确定以便开始使用数据库时,消息“无法读取来自数据库:未知数据类型:出现“文本”。我已经尝试修改 DatabaseUtil.props 文件,但似乎没有任何效果,所以如果有人能告诉我如何解决这个问题,我真的很高兴。谢谢

【问题讨论】:

    标签: sqlite weka


    【解决方案1】:

    我已阅读以下说明: https://waikato.github.io/weka-wiki/databases/#configuration-files

    现在这是我的 DatabaseUtils.props 文件,请更改 jdbcURL 条目

    # Database settings for sqlite 3.x
    #
    # General information on database access can be found here:
    # https://waikato.github.io/weka-wiki/databases
    #
    # url:     http://www.sqlite.org/
    # jdbc:    http://www.zentus.com/sqlitejdbc/
    # author:  Fracpete (fracpete at waikato dot ac dot nz)
    # version: $Revision: 5836 $
    
    # JDBC driver (comma-separated list)
    jdbcDriver=org.sqlite.JDBC,
    
    # database URL
    jdbcURL=jdbc:sqlite:/some/path/to/mydb.sqlite
    
    
    # specific data types
    # string, getString() = 0;    --> nominal
    # boolean, getBoolean() = 1;  --> nominal
    # double, getDouble() = 2;    --> numeric
    # byte, getByte() = 3;        --> numeric
    # short, getByte()= 4;        --> numeric
    # int, getInteger() = 5;      --> numeric
    # long, getLong() = 6;        --> numeric
    # float, getFloat() = 7;      --> numeric
    # date, getDate() = 8;        --> date
    # text, getString() = 9;      --> string
    # time, getTime() = 10;       --> date
    #SQLITE DATATYPES
    #NULL. The value is a NULL value.
    null=9
    #INTEGER. The value is a signed integer, stored in 1, 2, 3, 4, 6, or 8 bytes depending on the magnitude of the value.
    integer=5
    #REAL. The value is a floating point value, stored as an 8-byte IEEE floating point number.
    float=6
    #TEXT. The value is a text string, stored using the database encoding (UTF-8, UTF-16BE or UTF-16LE).
    
    TEXT=9
    text=9
    #BLOB. The value is a blob of data, stored exactly as it was input.
    
    
    # other options
    CREATE_DOUBLE=DOUBLE
    CREATE_STRING=varchar(2000)
    CREATE_STRING=TEXT
    CREATE_INT=INT
    CREATE_DATE=DATETIME
    DateFormat=yyyy-MM-dd HH:mm:ss
    checkUpperCaseNames=false
    checkLowerCaseNames=false
    checkForTable=true
    
    
    
    # All the reserved keywords for this database
    # Based on the keywords listed at the following URL (2009-04-13):
    # http://www.sqlite.org/lang_keywords.html
    Keywords=\
      ABORT,\
      ADD,\
      AFTER,\
      ALL,\
      ALTER,\
      ANALYZE,\
      AND,\
      AS,\
      ASC,\
      ATTACH,\
      AUTOINCREMENT,\
      BEFORE,\
      BEGIN,\
      BETWEEN,\
      BY,\
      CASCADE,\
      CASE,\
      CAST,\
      CHECK,\
      COLLATE,\
      COLUMN,\
      COMMIT,\
      CONFLICT,\
      CONSTRAINT,\
      CREATE,\
      CROSS,\
      CURRENT_DATE,\
      CURRENT_TIME,\
      CURRENT_TIMESTAMP,\
      DATABASE,\
      DEFAULT,\
      DEFERRABLE,\
      DEFERRED,\
      DELETE,\
      DESC,\
      DETACH,\
      DISTINCT,\
      DROP,\
      EACH,\
      ELSE,\
      END,\
      ESCAPE,\
      EXCEPT,\
      EXCLUSIVE,\
      EXISTS,\
      EXPLAIN,\
      FAIL,\
      FOR,\
      FOREIGN,\
      FROM,\
      FULL,\
      GLOB,\
      GROUP,\
      HAVING,\
      IF,\
      IGNORE,\
      IMMEDIATE,\
      IN,\
      INDEX,\
      INDEXED,\
      INITIALLY,\
      INNER,\
      INSERT,\
      INSTEAD,\
      INTERSECT,\
      INTO,\
      IS,\
      ISNULL,\
      JOIN,\
      KEY,\
      LEFT,\
      LIKE,\
      LIMIT,\
      MATCH,\
      NATURAL,\
      NOT,\
      NOTNULL,\
      NULL,\
      OF,\
      OFFSET,\
      ON,\
      OR,\
      ORDER,\
      OUTER,\
      PLAN,\
      PRAGMA,\
      PRIMARY,\
      QUERY,\
      RAISE,\
      REFERENCES,\
      REGEXP,\
      REINDEX,\
      RELEASE,\
      RENAME,\
      REPLACE,\
      RESTRICT,\
      RIGHT,\
      ROLLBACK,\
      ROW,\
      SAVEPOINT,\
      SELECT,\
      SET,\
      TABLE,\
      TEMP,\
      TEMPORARY,\
      THEN,\
      TO,\
      TRANSACTION,\
      TRIGGER,\
      UNION,\
      UNIQUE,\
      UPDATE,\
      USING,\
      VACUUM,\
      VALUES,\
      VIEW,\
      VIRTUAL,\
      WHEN,\
      WHERE
    
    # The character to append to attribute names to avoid exceptions due to
    # clashes between keywords and attribute names
    KeywordsMaskChar=_
    
    #flags for loading and saving instances using DatabaseLoader/Saver
    nominalToStringLimit=50
    idColumn=auto_generated_id
    

    【讨论】:

    【解决方案2】:

    尝试将 DatabaseUtils.prop 文件放在 Weka 主目录中。此外,在文件中,您应该在相应的扇区中添加诸如 TEXT=0 或 TEXT=9 之类的东西。

    【讨论】:

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