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Author: Nobody Source: CSDN Original text: https://blog.csdn.net/h1025372645/article/details/89191301 JDBC Java DataBase Connectivity,java database connection, in order to reduce the difficulty of operating data, java provides jdbc, according to the characteristics of java object-oriented, many operations are encapsulated. JDBC ...

I. Mass insertion of data MyISAM table insertion optimization, insertion before closing index updates. alter table xxx DISABLE KEYS; -- Turn off index updates ... -- insert data alter table xxx ENABLE KEYS; Insertion optimization of InnoDB tables: 1) The imported data is arranged according to the p ...

At ORACLE10g and 11g versions, the default log archive path for ORACLE is the flash-back recovery area ($ORACLE_BASE/flash_recovery_area).ORACLE has a limitation on this path: it only has 2G of space by default, and it is not only the default path for archive logs, but also the default address for backup files and flash back lo ...

A orm database Flutter plugin. I posted an article earlier. Hand-in-Hand Teaching You Elegant Use of ORM Database in Flutter Project Many people also put forward some valuable suggestions on consulting and using, saying that they do not want to write lua, which is not elegant enough, but also increases the cost of learning. On reflection, it is ...

1. parameterType (input type) (1) Pass simple types (such as int, which we can use directly) public Student getStudentById(Integer studentId); <select id="getStudentById" parameterType="int" resultType="student"> select * from tblstudent where studentId = #{studentId} </select> (2) Passing pojo objects     p ...

Case: (bottom) 1. Dynamic programming of metadata to convert RDD into DataFrame - > RDD2 Data Frame Programmatically 2. Reflect RDD-> DataFrame-> RDD2 DataFrame by Reflecting After RDD is converted to DataFrame, we can use Spark SQL to query any data that can be built into RDD, such as HDFS. This function is extre ...

Label PostgreSQL , Heap Only Tuple , HOT background PostgreSQL's current default storage engine generates a new version in the heap when updating records. The old version needs to recycle all index POINT associated with this version before it needs to recycle the old version after VACUUM is used. The KEY of the index of PG is the value of th ...

Chapter 3.2 describes the mapping relationship of the corresponding classes according to the steps in the book. It is found that at startup, all the tables previously built in Chapter 3.1 were deleted and re-established, and the data of Ingredient table was lost. Because of the use of JPA, hibernate was used by default, all tables were deleted ...

image.png The thinkphp framework is a free, open source, fast and simple object-oriented lightweight PHP development framework. Learn what is ThinkPHP overview, the directory structure of ThinkPHP projects, the controller of thinkphp, views, the process of building ThinkPHP projects, the configuration of thinkphp, the model o ...