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@pgsql/utils - npm

@pgsql/utils is a companion utility library for @pgsql/types, offering convenient functions to work with PostgreSQL Abstract Syntax Tree (AST) nodes and enums in a type-safe manner. This library facilitates the creation of AST nodes and simplifies the process of converting between enum names and their respective integer values, as defined in the PostgreSQL parser output.

  1. @pgsql/utils
  2. Installation
  3. Usage
  4. Related Projects
  5. Disclaimer

To add @pgsql/utils to your project, use the following npm command:

With the AST helper methods, creating complex SQL ASTs becomes straightforward and intuitive.

Explore the PostgreSQL Abstract Syntax Tree (AST) as JSON objects with ease using @pgsql/utils. Below is an example of how you can generate a JSON AST using TypeScript:

import * as t from '@pgsql/utils';
import { SelectStmt } from '@pgsql/types';
import { deparse } from 'pgsql-deparser';

const selectStmt: { SelectStmt: SelectStmt } = t.nodes.selectStmt({
  targetList: [
    t.nodes.resTarget({
      val: t.nodes.columnRef({
        fields: [t.nodes.aStar()]
      })
    })
  ],
  fromClause: [
    t.nodes.rangeVar({
      relname: 'some_amazing_table',
      inh: true,
      relpersistence: 'p'
    })
  ],
  limitOption: 'LIMIT_OPTION_DEFAULT',
  op: 'SETOP_NONE'
});
console.log(selectStmt);
// Output: { "SelectStmt": { "targetList": [ { "ResTarget": { "val": { "ColumnRef": { "fields": [ { "A_Star": {} } ] } } } } ], "fromClause": [ { "RangeVar": { "relname": "some_amazing_table", "inh": true, "relpersistence": "p" } } ], "limitOption": "LIMIT_OPTION_DEFAULT", "op": "SETOP_NONE" } }
console.log(await deparse(stmt))
// Output: SELECT * FROM some_amazing_table
import * as t from '@pgsql/utils';
import { SelectStmt } from '@pgsql/types';
import { deparse } from 'pgsql-deparser';

const query: { SelectStmt: SelectStmt } = t.nodes.selectStmt({
  targetList: [
    t.nodes.resTarget({
      val: t.nodes.columnRef({
        fields: [t.nodes.string({ sval: 'name' })]
      })
    }),
    t.nodes.resTarget({
      val: t.nodes.columnRef({
        fields: [t.nodes.string({ sval: 'email' })]
      })
    })
  ],
  fromClause: [
    t.nodes.rangeVar({
      relname: 'users',
      inh: true,
      relpersistence: 'p'
    })
  ],
  whereClause: t.nodes.aExpr({
    kind: 'AEXPR_OP',
    name: [t.nodes.string({ sval: '>' })],
    lexpr: t.nodes.columnRef({
      fields: [t.nodes.string({ sval: 'age' })]
    }),
    rexpr: t.nodes.aConst({
      ival: t.ast.integer({ ival: 18 })
    })
  }),
  limitOption: 'LIMIT_OPTION_DEFAULT',
  op: 'SETOP_NONE'
});

await deparse(createStmt);
// SELECT name, email FROM users WHERE age > 18
Creating Table Schemas Dynamically
// Example JSON schema
const schema = {
  "tableName": "users",
  "columns": [
    { "name": "id", "type": "int", "constraints": ["PRIMARY KEY"] },
    { "name": "username", "type": "text" },
    { "name": "email", "type": "text", "constraints": ["UNIQUE"] },
    { "name": "created_at", "type": "timestamp", "constraints": ["NOT NULL"] }
  ]
};

// Construct the CREATE TABLE statement
const createStmt = t.nodes.createStmt({
  relation: t.ast.rangeVar({ 
    relname: schema.tableName,
    inh: true,
    relpersistence: 'p'
  }),
  tableElts: schema.columns.map(column => t.nodes.columnDef({
    colname: column.name,
    typeName: t.ast.typeName({
      names: [t.nodes.string({ sval: column.type })]
    }),
    constraints: column.constraints?.map(constraint =>
      t.nodes.constraint({
        contype: constraint === "PRIMARY KEY" ? "CONSTR_PRIMARY" : constraint === "UNIQUE" ? "CONSTR_UNIQUE" : "CONSTR_NOTNULL"
      })
    )
  }))
});

// `deparse` function converts AST to SQL string
const sql = await deparse(createStmt, { pretty: true });

console.log(sql);
// OUTPUT: 

// CREATE TABLE users (
//  id int PRIMARY KEY,
// 	username text,
// 	email text UNIQUE,
// 	created_at timestamp NOT NULL 
// )

AS DESCRIBED IN THE LICENSES, THE SOFTWARE IS PROVIDED "AS IS", AT YOUR OWN RISK, AND WITHOUT WARRANTIES OF ANY KIND.

No developer or entity involved in creating Software will be liable for any claims or damages whatsoever associated with your use, inability to use, or your interaction with other users of the Software code or Software CLI, including any direct, indirect, incidental, special, exemplary, punitive or consequential damages, or loss of profits, cryptocurrencies, tokens, or anything else of value.

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