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Anonymous users2024-02-07create table [dbo].[Employee Data Sheet] (Number] [Char] (10) Collate Chinese taiwan stroke ci as null, Name] [Char] (10) Collate Chinese taiwan stroke ci as null, Gender] [Char] (10) Collate Chinese taiwan stroke ci as null, Department] [char] (10) collate Chinese taiwan stroke ci as null, salary] [char] (10) collate Chinese taiwan stroke ci as null
on [primary]
gocreate table [dbo].[Department Data Sheet] (Department Number] [Char] (10) Collate Chinese taiwan stroke ci as null, Department Name] [char] (10) collate Chinese taiwan stroke ci as null, Department Functions] [char] (10) collate Chinese taiwan stroke ci as null, Department Head[char] (10) collate Chinese taiwan stroke ci as null
on [primary]go
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Anonymous users2024-02-06Create a table: create table Table Table Name (Column 1 Name, Column 1 Type, Column 2 Name, Column 2 Type, Column 3 Name, Column 3 Type, Column 4 Name, Column 4 Type); Insert a record: insert into table name values('Column 1 contents','Column 2 contents','Column 3 contents','Column 4 contents');
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Anonymous users2024-02-05Graphical manipulation is not enough. .I don't know how to command, just use graphics.
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Anonymous users2024-02-041. First of all, select a database of your own (here my database name is "vcomany"), find "Table", right-click "Table", and select "New Table".
2. Enter the configuration of the column, the column name is id, the type is int (it must be int, otherwise it cannot be automatically grown), and then the null value is not allowed.
3. Then set the id as the primary key, which is the unique identifier of this **.
4. Then right-click on the column and select "Attribute Settings".
5. Find the "Identity Specification" in the "Attribute Settings" and set the "Yes Identity" to "Yes", and then set the "Identity Increment" and "Identity Seed" (generally the default).
6. Now try to add content, the id column cannot be added, just add the content of other columns, the id column will be automatically generated, when doing ** background, when inserting data, you can not insert the value of id.
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Anonymous users2024-02-03You can't do it unless you cancel the automatic numbering and control the number sequence yourself, but it's very cumbersome.
The automatic numbering type is a long integer, which is a number, and cannot be identified by letters.
It is recommended that you change the name of the primary key of each table, such as name keyid, which is clear at a glance.
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Anonymous users2024-02-02Does your "tick" mean built? Is it because there are too many contents in the health record? If you have an excel sheet, you can import it, or you can lose it.
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Anonymous users2024-02-01This means that the horizontal table is converted to a vertical table.
In the usual database design, we tend to store one record per row. A vertical table uses the relationship between "key" and "value" to store data and field names, and each row of data only has the field name and the corresponding data. All the data seems to be "upright".
This is indeed conducive to maintenance, such a complete data record, can be n rows, or n + m rows.
However, it is very difficult to search for data, if it is just a normal query, if it is a complex nested query, the speed and SQL writing will be much more complicated.
In addition, in addition to the key value of each row, an id should be added to distinguish the data with different numbers of bars.
Finally, there is the id field name of the numeric table structure.
Finally, this structure is not suitable for tables with large data volumes, and retrieval will be particularly slow if not optimized well. Personally, I suggest that if there is a possibility of generating more than 10 million rows of data (not table data, but the number of data records, a data may have multiple fields, and each field accounts for a table data) (based on MySQL), it is best to consider other methods.
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Anonymous users2024-01-31What he means is to make a normal table that you want, and then make a table that stores the fields (column names) of that table.
If you want to work with a normal table in the program, you first read the field record table and then list its column names.
Later, if you modify the fields of the normal table, then change them accordingly in the field record table, so that you don't have to change the program.
Tools Material: Management Studio.
1. First, on the desktop, click on the "Management Studio" icon. >>>More
Method 1: Leverage the Metadata Locks view.
This method is only applicable to MySQL versions or later, and the performance schema adds Metadata Locks, which can easily locate the global lock session if the probe with metadata lock enabled before locking (the default is not enabled). >>>More
The database is generally composed of many tables, for example, the school builds a database, which can build a student table (including the student's name, age, student number, class, date of birth), a teacher table (including the teacher's name, age, teaching class, teaching category), a report sheet (including the student's student number, and the grades of each subject), etc. These are the ways in which the files are stored in the database, and try to make sure that the items in a table are closely related and have the same attributes, if this condition cannot be met, a table must be built (the redundancy of the built table has 4 levels). In order to meet the user's query needs, we also need to make a number of views, for example, you can make a view of his items have the name of the student, age, grades of each subject, and the teacher of each subject, etc., we can also export new items according to the existing items, for the purpose of simplicity, for example, the view can add an average grade, we add different permissions and roles to each view, and provide it to different people to query to protect the security of the database. >>>More
select ,from emp e left jion dept don ;
Left Company. The left link is, the left side prevails, and the right side is useless to make up for it. >>>More
Specific software analysis.