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- Learn about SQL injection and how to fix it
- SQL injection means that the web application does not judge the legality of the user input data or does not filter it strictly. The attacker can add additional SQL statements at the end of the pre-defined query statements in the web application without the administrator's knowledge. Implement illegal operations in order to deceive the database server into executing unauthorized arbitrary queries, thus further
- SQL 3336 2021-01-28 18:17:45
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- A flip-flop has several steady states
- The flip-flop has two stable states, which can represent binary numbers 0 and 1 respectively. It can maintain the stable state without external trigger; under external trigger, the two stable states can be converted into each other, and the converted stable state can be maintained for a long time. This is Enables flip-flops to memorize binary information and is often used as a binary storage unit.
- SQL 19856 2023-01-13 00:40:50
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- How to set foreign keys in database sql statement
- Methods for setting foreign keys in database SQL statements: 1. Add foreign key constraints [alter table add foreign key (foreign key field) references from table main table (primary key field)]; 2. Delete foreign key constraints [alter table table name drop foreig 】.
- SQL 80943 2023-01-13 00:40:46
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- What type of database management system is sql?
- SQL, the full name of SQL Server, is a relational database management system. The SQL Server database engine provides more secure and reliable storage capabilities for relational and structured data, allowing you to build and manage highly available and high-performance data applications for your business.
- SQL 13965 2023-01-13 00:40:45
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- Understand inner joins, left outer joins, and right outer joins of sql statements
- When you first learn databases, do you have some doubts about the connection query in DQL? Do you know when and what kind of connection query should be used in what scenario? Don't worry, let me introduce to you the understanding of the characteristics and application scenarios of inner joins, left outer joins, and right outer joins in the SQL tutorial column for your reference.
- SQL 4208 2021-01-15 10:20:46
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- Troubleshooting SQL injection issues
- What is SQL injection? Take a look at the definition of Baidu Encyclopedia. The following SQL tutorial uses an example to explain what SQL injection is: Create a new database, create a table, and add two rows of data: use db1;create table user(id int...
- SQL 1812 2021-01-12 09:22:53
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- SQL optimization minimalist rules that you must not know
- SQL Tutorial As the standard language of relational database, it is one of the essential skills for IT practitioners. SQL itself is not difficult to learn, and writing query statements is also very easy, but it is difficult to write query statements that can run efficiently.
- SQL 2262 2021-01-02 11:23:42
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- Introducing ten steps to fully understand SQL
- Many programmers view SQL as a scourge. SQL is one of the few declarative languages that operates completely differently from the command line languages, object-oriented programming languages, and even functional languages we are familiar with (although some people think that the SQL language is also a functional language ).
- SQL 2431 2020-12-29 17:57:49
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- Solving SQL problems will definitely take your understanding of MySQL one step further!
- The structure of the attribute table (product_props) introduced in the SQL tutorial column is as follows. Data volume is more than 800W. Field name type description id int id pn_id int attribute type pv_id int attribute value product_id int product ID.
- SQL 4843 2020-12-26 17:42:09
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- Record slow SQL optimization practice
- Introduction to sql tutorial After optimizing sql slow query, we found the following types of problems in our system: 1. No index built: no index built for the entire table; 2. Index miss: there is an index, but the index is under some query conditions Missed; 3. Searched for additional non-essential fields, resulting in table return; 4. Sorting, aggregation...
- SQL 6171 2020-12-25 17:23:57
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- What are the sql query statements?
- SQL query statement: 1. View the table structure [SQL>DESC emp]; 2. Query all columns [SQL>SELECT * FROM emp]; 3. Query the specified columns; 4. Query the specified rows; 5. Use arithmetic expressions; 6 , use logical operation symbols.
- SQL 68838 2023-01-13 00:40:45
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- Learn MyBatis dynamic SQL
- SQL tutorial introduces dynamic SQL. One of the powerful features of MyBatis is its dynamic SQL. If you have experience using JDBC or other similar frameworks, you will understand the pain of splicing SQL statements based on different conditions. For example, when splicing, make sure you don't forget to add necessary spaces.
- SQL 2793 2020-12-09 17:46:13
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- Understanding SQL Advanced Advanced
- The SQL tutorial column introduces 10 advanced advancements. Friends in need can take a look.
- SQL 9683 2020-12-04 17:06:03
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- Learn to process tens of millions of records in SQL Server
- The sql tutorial column introduces how to process tens of millions of records.
- SQL 9511 2020-11-27 16:42:29
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