CSV import as a table and db connection rework

- Add csv to existing db #32
- [RFE] Simplify working with temporary tables #53

src/lib/database/_statements.js

@@ -1,3 +1,5 @@
+import sqliteParser from 'sqlite-parser'
+
 export default {
   * generateChunks (arr, size) {
     const count = Math.ceil(arr.length / size)
@@ -9,14 +11,14 @@ export default {
     }
   },
 
-  getInsertStmt (columns) {
+  getInsertStmt (tabName, columns) {
     const colList = `"${columns.join('", "')}"`
     const params = columns.map(() => '?').join(', ')
-    return `INSERT INTO csv_import (${colList}) VALUES (${params});`
+    return `INSERT INTO "${tabName}" (${colList}) VALUES (${params});`
   },
 
-  getCreateStatement (columns, values) {
-    let result = 'CREATE table csv_import('
+  getCreateStatement (tabName, columns, values) {
+    let result = `CREATE table "${tabName}"(`
     columns.forEach((col, index) => {
     // Get the first row of values to determine types
       const value = values[0][index]
@@ -40,5 +42,49 @@ export default {
     })
     result = result.replace(/,\s$/, ');')
     return result
+  },
+
+  getAst (sql) {
+    // There is a bug is sqlite-parser
+    // It throws an error if tokenizer has an arguments:
+    // https://github.com/codeschool/sqlite-parser/issues/59
+    const fixedSql = sql
+      .replace(/(tokenize=[^,]+)"tokenchars=.+?"/, '$1')
+      .replace(/(tokenize=[^,]+)"remove_diacritics=.+?"/, '$1')
+      .replace(/(tokenize=[^,]+)"separators=.+?"/, '$1')
+      .replace(/tokenize=.+?(,|\))/, 'tokenize=unicode61$1')
+
+    return sqliteParser(fixedSql)
+  },
+
+  /*
+   * Return an array of columns with name and type. E.g.:
+   * [
+   *   { name: 'id',    type: 'INTEGER' },
+   *   { name: 'title', type: 'NVARCHAR(30)' },
+   * ]
+  */
+  getColumns (sql) {
+    const columns = []
+    const ast = this.getAst(sql)
+
+    const columnDefinition = ast.statement[0].format === 'table'
+      ? ast.statement[0].definition
+      : ast.statement[0].result.args.expression // virtual table
+
+    columnDefinition.forEach(item => {
+      if (item.variant === 'column' && ['identifier', 'definition'].includes(item.type)) {
+        let type = item.datatype ? item.datatype.variant : 'N/A'
+        if (item.datatype && item.datatype.args) {
+          type = type + '(' + item.datatype.args.expression[0].value
+          if (item.datatype.args.expression.length === 2) {
+            type = type + ', ' + item.datatype.args.expression[1].value
+          }
+          type = type + ')'
+        }
+        columns.push({ name: item.name, type: type })
+      }
+    })
+    return columns
   }
 }