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从 DDL 中提取元数据

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从 DDL 中提取元数据

我创建了一个文件，其中包含特定模式中存在的表列表。我需要提取每个表的列详细信息并需要将其写入另一个文件

describe test_table
+-----------+------------+------------+
| col_name  | data_type  |Comment     |
+-----------+------------+------------+
| Name      | string     |My Name     |
| Age       | string     |My Age      |
+-----------+------------+------------+

输出文件应包含以下详细信息。

test_table,Name,String,My Name
test_table,Age,string,My Age

答案1

$ cat extract-columns.pl
#!/usr/bin/perl -l

while(<>) {
  # Is the current line a "describe" line?
  if (m/describe\s+(.*)/i || eof) {
    $table = $1;
    next;
  };

  # skip header lines, ruler lines, and empty lines
  next if (m/col_name|-\+-|^\s*$/);

  # remove pipes and spaces at beginning and end of line
  s/^\|\s*|\s*\|\s*$//g;

  # remove spaces surrounding pipe characters
  s/\s*\|\s*/|/g;

  # extract field name by splitting input line on pipe chars
  my ($name, $type, $comment) = split /\|/;
  print join(",", $table, $name, $type, $comment);
}

示例输出：

$ ./extract-columns.pl table2.txt 
test_table,Name,string,My Name
test_table,Age,string,My Age

答案2

和awk：

awk -v OFS="," 'NR==1{ tblName=$2; FS="|"; next }
NF>1 && NR>4{ $1=tblName; gsub(/ *, */, ","); sub(/,$/, ""); print }' infile

输出：

test_table,Name,string,My Name
test_table,Age,string,My Age

我们将从gsub()每个字段中删除前导和尾随空格；
我们sub()正在删除结尾的逗号。

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