javascript 如何使用模块mysql在nodejs上列出mysql中的列
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how to list column in mysql on nodejs with module mysql
提问by goten
I want to list columns in a table using module mysql on nodejs
我想在 nodejs 上使用模块 mysql 列出表中的列
When I run the query :
当我运行查询时：
SHOW COLUMNS FROM tableName WHERE FIELD = columnName
It's work fine, I can know if the column exist or not.
它工作正常，我可以知道该列是否存在。
But I want to list the columns and I get a list of object and I don't what to do with that and if I get the good result.
但我想列出列，我得到一个对象列表，我不知道该怎么做，如果我得到了好的结果。
I tried :
我试过 ：
SHOW COLUMNS FROM tableName
DESCRIBE tableName
with both queries I get a list of object
通过这两个查询，我得到了一个对象列表
{ catalog: 'def',
db: 'information_schema',
table: 'COLUMNS',
orgTable: 'COLUMNS',
name: 'Field',
orgName: 'COLUMN_NAME',
filler1: ,
charsetNr: 33,
length: 192,
type: 253,
flags: 1,
decimals: 0,
filler2: ,
default: undefined,
zeroFill: false,
protocol41: true }
{ catalog: 'def',
db: 'information_schema',
table: 'COLUMNS',
orgTable: 'COLUMNS',
name: 'Type',
orgName: 'COLUMN_TYPE',
filler1: ,
charsetNr: 33,
length: 589815,
type: 252,
flags: 17,
decimals: 0,
filler2: ,
default: undefined,
zeroFill: false,
protocol41: true }
{ catalog: 'def',
db: 'information_schema',
table: 'COLUMNS',
orgTable: 'COLUMNS',
name: 'Null',
orgName: 'IS_NULLABLE',
filler1: ,
charsetNr: 33,
length: 9,
type: 253,
flags: 1,
decimals: 0,
filler2: ,
default: undefined,
zeroFill: false,
protocol41: true }
{ catalog: 'def',
db: 'information_schema',
table: 'COLUMNS',
orgTable: 'COLUMNS',
name: 'Key',
orgName: 'COLUMN_KEY',
filler1: ,
charsetNr: 33,
length: 9,
type: 253,
flags: 1,
decimals: 0,
filler2: ,
default: undefined,
zeroFill: false,
protocol41: true }
{ catalog: 'def',
db: 'information_schema',
table: 'COLUMNS',
orgTable: 'COLUMNS',
name: 'Default',
orgName: 'COLUMN_DEFAULT',
filler1: ,
charsetNr: 33,
length: 589815,
type: 252,
flags: 16,
decimals: 0,
filler2: ,
default: undefined,
zeroFill: false,
protocol41: true }
{ catalog: 'def',
db: 'information_schema',
table: 'COLUMNS',
orgTable: 'COLUMNS',
name: 'Extra',
orgName: 'EXTRA',
filler1: ,
charsetNr: 33,
length: 90,
type: 253,
flags: 1,
decimals: 0,
filler2: ,
default: undefined,
zeroFill: false,
protocol41: true }
The function I use is the following :
我使用的功能如下：
var mysql = require('mysql');
var connection = mysql.createConnection({
host : "host",
user : "user",
password : "pass",
database : "db"
});
connection.query(myQuery, function(err, rows, fields){
if(err) console.log(err);
if(fields) console.log(fields);
if(rows) console.log(rows);
});
If someone have a solution for me I tried also to look in information_schema and get the same result. Thanks you in advance.
如果有人对我有解决方案，我也尝试查看 information_schema 并获得相同的结果。提前谢谢你。
At the same time if someone can tell how to use show table I get a similar result.
同时，如果有人能告诉我如何使用 show table，我会得到类似的结果。
回答by Andrey Sidorov
You are printing 'fields' first, which is description of fields in the SHOW COLUMNSresponse. Response rows itself looks like this:
您首先打印“字段”，这是SHOW COLUMNS响应中字段的描述。响应行本身看起来像这样：
[
{
Field: 'id',
Type: 'int(11) unsigned',
Null: 'NO',
Key: 'PRI',
Default: null,
Extra: 'auto_increment'
}
/* , ... */
]
So first column name, for example is:
例如，第一个列名是：
connection.query('SHOW COLUMNS FROM test', function(err, rows, fields){
console.log(rows[0].Field);
});
