大约有 40,000 项符合查询结果（耗时：0.0593秒） [XML]
What is a 'multi-part identifier' and why can't it be bound?
I continually get these errors when I try to update tables based on another table. I end up rewriting the query, change the order of joins, change some groupings and then it eventually works, but I just don't quite get it.
...
What is the difference between LR, SLR, and LALR parsers?
...s of LR parsers, but what is the actual difference as far as their parsing tables are concerned?
8 Answers
...
MySQL InnoDB not releasing disk space after deleting data rows from table
I have one MySQL table using the InnoDB storage engine; it contains about 2M data rows. When I deleted data rows from the table, it did not release allocated disk space. Nor did the size of the ibdata1 file reduce after running the optimize table command.
...
Database Design for Revisions?
...
Do not put it all in one table with an IsCurrent discriminator attribute. This just causes problems down the line, requires surrogate keys and all sorts of other problems.
Design 2 does have problems with schema changes. If you change the Employees...
Query to list number of records in each table in a database
How to list row count of each table in the database. Some equivalent of
21 Answers
21...
ActiveRecord: List columns in table from console
I know that you can ask ActiveRecord to list tables in console using:
8 Answers
8
...
How to list all the available keyspaces in Cassandra?
...nt to do this outside of the cqlsh tool you can query the schema_keyspaces table in the system keyspace. There's also a table called schema_columnfamilies which contains information about all tables.
The DESCRIBE and SHOW commands only work in cqlsh and cassandra-cli.
...
Using a Single Row configuration table in SQL Server database. Bad idea?
...
I have done this two ways in the past - a single row table and a key/value pair table - and there are positives and negatives to each approach.
Single Row
positive: the values are stored in the correct type
positive: it is easier to deal with in code (due to the above)
positiv...
Is it possible to use 'else' in a list comprehension? [duplicate]
...t; [a if a else 2 for a in [0,1,0,3]]
[2, 1, 2, 3]
So for your example,
table = ''.join(chr(index) if index in ords_to_keep else replace_with
for index in xrange(15))
share
|
imp...
How to find the JVM version from a program?
...any other system properties related to the current Java version. Here is a table of them:
Property Value (OpenJDK 12) Value (Oracle JRE 8u201) Value (Sun JRE 5u22) Description
-----------------------------...