大约有 9,000 项符合查询结果（耗时：0.0253秒） [XML]
Quickly reading very large tables as dataframes
...ata is passed to and from R in a binary format, which is faster.) read.csv.sql in the sqldf package, as described in JD Long's answer, imports data into a temporary SQLite database and then reads it into R. See also: the RODBC package, and the reverse depends section of the DBI package page. MonetD...
PostgreSQL Autoincrement
I'm switching from MySQL to PostgreSQL and was wondering how I can do autoincrement values. I saw in the PostgreSQL docs a datatype "serial", but I get syntax errors when using it (in v8.0).
...
VC菜单命令详解(文件打开、保存与关闭) - C/C++ - 清泛网 - 专注C/C++及内核技术
...cument::OnNewDocument()首先调用DeleteContents()删除原文档内容，使用m_strPathName.Empty()
清除当前文档路径，SetModifiedFlag(FALSE)。
2.ID_FILE_OPEN
CWinApp::OnFileOpen调用CDocManager::OnFileOpen。
|
CDocManager::OnFileOpen首先显示文件打开对...
How to check if a table exists in a given schema
...tion in a function. Example:
Check if sequence exists in Postgres (plpgsql)
A query like above avoids possible exceptions and is therefore slightly faster.
to_regclass(rel_name) in Postgres 9.4+
Much simpler now:
SELECT to_regclass('schema_name.table_name');
Same as the cast, but it retur...
Howto: Clean a mysql InnoDB storage engine?
Is it possible to clean a mysql innodb storage engine so it is not storing data from deleted tables?
2 Answers
...
Similarity String Comparison in Java
... Here's an article showing how combine Levenshtein with an efficient SQL query: literatejava.com/sql/fuzzy-string-search-sql
– Thomas W
Apr 26 '14 at 2:11
...
How to install mongoDB on windows?
...efault. Lets go query that.
But how without any management studios? Unlike SQL, we have to depend on the command prompt. Yes exactly the same command prompt… our good old command prompt… Heiiiii.. Don’t get afraid yes it’s our old command prompt only.
Ok let’s go and see how we are going ...
SSL is not enabled on the server
...uld establish DB connection without SSL encryption, like that:
db, err := sql.Open("postgres", "user=test password=test dbname=test sslmode=disable")
share
|
improve this answer
|
...
Primary key/foreign Key naming convention [closed]
... same name in both tables (convention #2), you can use the USING syntax in SQL to save some typing and some boilerplate noise:
SELECT name, address, amount
FROM employees JOIN payroll USING (employee_id)
Another argument in favor of convention #2 is that it's the way the relational model was de...
How to enable Ad Hoc Distributed Queries
When I run a query with OPENROWSET in SQL Server 2000 it works.
4 Answers
4
...