1. Background
During the database development and maintenance process, we often need to execute a large number of SQL statements. Sometimes these SQL statements are saved in a file for easier batch execution. To facilitate processing of these SQL files in Go, we can write a function to read and parse statements in SQL files.
2. Implementation ideas
Open the SQL file.
Read the file content line by line.
Filter out comments and blank lines.
Splice SQL statements with semicolon (;) as the ending character.
Save the spliced SQL statements to the slice.
Returns a slice containing all SQL statements.
3. Code implementation
The following are functions implemented in Go language to read and parse SQL files:
package main
import (
"bufio"
"io"
"os"
"strings"
)
// readSQLFile Reads the SQL file and divides the SQL statements in the file into string slices and returns.func readSQLFile(filename string) ([]string, error) {
var statements []string // Used to store split SQL statements file, err := (filename) // Open the file if err != nil {
return nil, err // If an error occurs when opening the file, return an error }
defer () // Finally close the file reader := (file) // Create a buffer reader var stmt // Used to build a single SQL statement var inMultiLineComment bool // Whether the tag is in a multi-line comment for {
line, err := ('\n') // Read line by line if err != nil {
if err == { // If you read the end of the file if () > 0 { // If there is content in stmt, it means there are still unfinished SQL statements. ((line)) // Remove the end blank characters statements = append(statements, ()) // Add the built SQL statement to the slice }
break // End the loop }
return nil, err // If an error occurs during reading, return an error }
line = (line) // Remove whitespace characters at the beginning and end of the line // Handle multi-line comments if inMultiLineComment {
if (line, "*/") { // Check whether the comment is finished line = (line, "*/")[1] // Get the content after the comment is finished inMultiLineComment = false // Update status } else {
continue // If the comment does not end, skip the current line }
}
// Process single line comments if (line, "/*") {
commentEndIndex := (line, "*/") // Find the location where the comment ends if commentEndIndex == -1 { // If the comment does not end inMultiLineComment = true // Update status continue
} else {
line = line[commentEndIndex+2:] // Get the content after the comment is finished }
}
// Skip single line comments if (line, "--") {
continue
}
(line) // Add the current line to stmt // Check whether it is the end of the SQL statement if (line, ";") {
statements = append(statements, ()) // Add the built SQL statement to the slice () // Reset stmt and prepare to build the next SQL statement }
}
return statements, nil // Return to the split SQL statement slice}
func main() {
// Example usage statements, err := readSQLFile("") // Read SQL files if err != nil {
panic(err) // If an error occurs, interrupt the program }
for _, stmt := range statements { // traverse and print each SQL statement println(stmt)
}
}4. Code analysis
Open SQL file: Use the function to open the file and use the defer keyword to ensure that the file is closed at the end of the function.
Read file content line by line: Create a buffer reader and read file content line by line by looping call ReadString function.
Filter out comments and blank lines: filter out comments and blank lines by determining whether the line's beginning contains comment identifiers such as /, /, and –.
Splicing SQL statements: Use type splicing SQL statements to improve performance.
Save the spliced SQL statement to the slice: When encountering a semicolon (;), add the spliced SQL statement to the slice and reset the stmt variable.
Returns a slice containing all SQL statements: When the file is read, returns a slice containing all SQL statements.
5. Summary
This article describes how to write a simple function in Go language for reading and parsing SQL files. Through this function, we can easily extract statements in SQL files and perform subsequent operations. Hopefully this example can help you process SQL files in actual projects.
This is the article about Golang's implementation method of reading and parsing SQL files. For more related go to read the content of SQL files, please search for my previous articles or continue browsing the related articles below. I hope everyone will support me in the future!