Oracle基础知识总结

0X01 Oracle常用SQL语句汇总

（1）获取数据表名和行数：

select OWNER, TABLE_NAME, NUM_ROWS from all_tables order by NUM_ROWS desc

（2）获取数据表的字段名和值为空的行数：

select COLUMN_NAME,COLUMN_ID,NUM_NULLS from all_tab_columns where  TABLE_NAME = 'XXX' and OWNER = 'XXX' order by COLUMN_ID

（3）获取数据表和字段名的注释信息：

select a.OWNER, a.TABLE_NAME,c.COMMENTS,a.COLUMN_NAME,b.COMMENTS,a.COLUMN_ID,a.NUM_NULLS from all_tab_columns a
left join dba_col_comments b on a.COLUMN_NAME = b.COLUMN_NAME
left join user_tab_comments c on c.TABLE_NAME = a.TABLE_NAME
where a.OWNER = b.OWNER and b.OWNER='XXX' and a.TABLE_NAME = 'XXX' and b.TABLE_NAME =a.TABLE_NAME
order by a.COLUMN_ID

（4）获取查询结果的前10行：

select * from Table_Name where rownum <=10

（5）查看表操作历史记录：

select * from v$sqlarea
select * from ALL_TAB_MODIFICATIONS

0X02 Oracle导出数据到Excel表

#!/usr/bin/python2.7 
# -*- coding: UTF-8 -*-
import cx_Oracle
import xlsxwriter
import sys
reload(sys)
sys.setdefaultencoding('utf8')
def conn_db():
    conn_str = u'username/[email protected]:1521/orcl'
    con = cx_Oracle.connect(conn_str)
    return con
def close_db(con):
    con.close()
def Query_TabName(con):
    cursor = con.cursor()
    col_vaule = ''
    sql = 'select * from TabName where COLUMN_NAME = %s' %(col_vaule)
    cursor.execute(sql)
    return cursor
def Save_DB2Excel():
    con = conn_db()
    Cursor = Query_TabName(con)
    filename = u'./excel/信息文件.xlsx'
    workbook = xlsxwriter.Workbook(filename)
    worksheet = workbook.add_worksheet()
    # Add a bold format to use to highlight cells. 设置粗体，默认是False
    bold = workbook.add_format({'bold': True})
    bg_color = workbook.add_format({'bg_color':'FF0033'})
    # Write some data headers. 带自定义粗体blod格式写表头
    worksheet.write('A1', 'COLUMN_NAME', bold)
    rows = 1
    while True:
        result = Cursor.fetchone() #依次读取一行数据
        if result == None:
            break
        #依次写入一行各字段数据
        for cols in range(len(result)):
            # print type(result[cols])
            if result[cols] is not None:
                if type(result[cols]) is str:
                    worksheet.write(rows, cols, result[cols].decode('gbk')) #字符串类型 需要解码
                else:
                    worksheet.write(rows, cols, result[cols],bg_color)
            else:
                worksheet.write(rows, cols, '——' )
        print rows
        rows = rows + 1
    Cursor.close()
    close_db(con)
    print '正在保存数据....'
    workbook.close()
    print("EXIT!")  
if __name__ == "__main__":
    Save_DB2Excel()

备注：需要下载Oracle官方32位客户端，并在系统环境变量Path里添加该路径(客户端的位数与所安装Python的位数一致)

[1] “Python cx_Oracle Client Library Cannot Be Loaded”的解决办法

Oracle基础知识总结

猜你喜欢