postgres get length of column

Operating system version[Root@web103 ~]# More/etc/issueCentOS release 5.9 (Final)Kernel \ r \m[Root@web103 ~]# Uname-aLinux web103 2.6.18-348.el5 #1 SMP Tue 8 17:53:53 EST 2013 x86_64 x86_64 x86_64 gnu/linuxdownload corresponding PostgreSQL

The latest I/O statistics Tool in CentOS As a Linux system administrator, it is essential to count various types of IO. Iostat is obviously the most important statistical tool. However, iostat is not the focus of this article, because there are

Postgres 9.3 is currently under intensive development. A new feature worth noting in this version is the JSON data type. After reading the new functions for data generation article, let's take a look at the description of the new JSON feature in the

Then read with me. PostgreSQL source Code (ix)--executor (the--scan node (top) of the query execution module), this chapter ends the remaining seven scan nodes. T_SubqueryScanState, T_FunctionScanState, T_ValuesScanState, T_CteScanState,

A database index is an identity attached to a table field to increase query speed. Seen a lot of people mechanically understand the concept of indexing and think that adding indexes only benefits no harm. Here you want to summarize the previous

A database index is an identity attached to a table field to increase query speed.    Seen a lot of people mechanically understand the concept of indexing and think that adding indexes only benefits no harm. Here you want to summarize the previous

For an understanding of the index refer to this post:Http://www.cnblogs.com/newpanderking/p/3781043.htmlTypes of indexes and creating posts:http://blog.csdn.net/xluren/article/details/32746183Advantages and disadvantages of the index:MySQL Tutorial:

Join nodeThe Join node has the following three types: T_NestLoopState, T_MergeJoinState, T_HashJoinState,The connection type node corresponds to the join operation in the relational algebra, and the following connection types are defined in

Ipvs9.3 is currently under development. A new feature worth noting in this version is the JSON data type. After reading newfunctionsfordatagener Postgres 9.3 is currently under intensive development. A new feature worth noting in this version is the

Python Database FrameworkMost database engines have Python packages, including open source packages and commercial packages. Flask does not restrict what type of database package you use, so you can choose to use MySQL, Postgres, SQLite, Redis,