事实上，面向文档的数据库中根本不存在表、行、列或关系。
In fact, there are no tables, rows, columns or relationships in a document-oriented database at all.
如果已经存在表，那么清单2中的代码将清空该表。
The code in Listing 2 clears the table if it's already there.
在这里还可以做更多操作：例如，如果数据库中不存在表，则创建表。
More can be done here: create a table, for example, if the table doesn't exist in the database.
账号数据储存在表accounts的mysql数据库mysqldb中。
The account data is stored in the mysql database mysqldb in the table Accounts.
当然，它在被人发现或制造前，就是一种元素周期表使得我们期待其存在的元素。
Of course, it was an element the periodic table let us to expect existed before anyone had found it or made it.
创建数据库时不存在用户临时表空间。
No user temporary table Spaces exist when a database is created.
这个过程的操作要求 SYSTOOLSPACE表空间已经存在。
The operation of this procedure requires the existence of the SYSTOOLSPACE table space.
请注意各种样式表间存在几个差异。
Notice that there are several differences among the various style sheets.
下面需要使用DB2检查是否存在新建表，如清单12 所示。
You should now be able to use DB2 to verify the new table exists, as shown in Listing 12.
如果基线不存在，这个表函数与MON_GET _ TABLE等效。
If no baseline exists, this table function is equivalent to MON_GET_TABLE.
如果正在使用数据库中已经存在的表，则不需要在Python中定义列。
If you're working with tables that already exist in a database, you don't need to define the columns in Python.
路由器将其目的地址换成它保存在地址转换表中的那个，然后将数据包发送到那台计算机。
It changes the destination address to the one saved in the address translation table and sends it to that computer.
然而，虚表也存在一些缺点。
在我们的例子中，我们指定了一个不存在的表的名称。
目标工作表必须已经存在，并且必须已经定义了标题行的字段。
The target worksheet must already exist and must already have the fields of the header row defined.
然后，脚本将把信息保存在XML日程表文件中，该文件存储了所有的约会信息。
The script will then save the information within the XML calendar file that stores all of the appointments.
在第三阶段，用更具体的关系来修改这些将存在于不同表的实体间的概念。
In the third phase, you modify the concepts with more specific relationships that will exist between entities in the various tables.
维度模型中的事实表与其他所有维度表之间存在单一连接。
The fact table in the dimensional model has a single join with all the other dimension tables.
如果某个特性没有列出在表中，可以认为该特性存在于该表所列的所有版本中(大多数情况下)。
If a feature is not listed in the table, you can assume (for the most part) that the feature exists in all editions included in the table.
如果特定的表空间包含的表与其他的表空间中的表存在引用限制，那么首先恢复它不会改进可用性。
Restoring a particular table space first does not improve availability if it contains tables with referential constraints to tables in other table spaces.
首先确定在注册表中存在与输入服务名精确匹配的项。
First determine if there is an exact match with the input service name in the registry.
会话锁还可保存在被锁定的表中(或表集合的根表中)。
Session locks can also be kept on the table that is being locked (or the root table of a set of tables).
使用视图，各类搜索所需的所有数据都在一个位置，但是活动数据实际上存在于其他表中。
Using a view, all the data needed for every kind of search is in one place, even though the live data actually lives in other tables.
登录模块还可以使用一个来自凭证高速缓存的已存在的TGT或是来自密钥表的已存在的密钥。
The login module can also use an existing TGT from a credentials cache or an existing secret key from a key table.
但是，我认为由于这些详细的估计和进度表，这里存在大量错误的信心。
But I think there's a lot of false confidence that gets built up by these detailed estimates and detailed schedules.
这样的操作会花费一定的时间，因此您希望在工具运行期间具有对预先存在的表数据的虚拟不间断访问。
Such operations can take a substantial amount of time, and you will appreciate having virtually uninterrupted access to pre-existing table data while the utility is running.
此外，如果ALLOWREADACCESS加载操作失败或者被中断，预先存在的表数据仍然可以被读取。
Moreover, if an ALLOW read ACCESS load operation fails or is aborted, pre-existing table data can still be read.
那些有很多盘区、或者至少曾经有过的表，存在两个问题。
There are two problems with tables that have lots of extents, or at least there used to be.
表级谓词通常也存在于一些维度表中。
Table-level predicates typically exist on some dimension tables as well.
表级谓词通常也存在于一些维度表中。
Table-level predicates typically exist on some dimension tables as well.
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